Sub-Micron Adjustable Mount for Supporting a Component and Method

ABSTRACT

An optical assembly includes a light path and at least one optic to be positioned in the path. A support arrangement supports the optic having a foot arrangement including at least one foot that receives a direct manipulation with the foot slidingly engaged against a support surface to move the optic relative to the light path. Movement of the foot may move the optic along a predetermined path. The foot defines a footprint for engaging the support surface and receives the direct manipulation in a way which changes the footprint on the support surface to move the optic responsive to changes in the footprint. A movement arrangement may selectively bias the foot against the support surface during a movement mode, intended to permit movement of the foot against the support surface, and in a locked mode, intended to lock the foot against the support surface.

RELATED APPLICATION

The present application is a divisional application of co-pendingapplication Ser. No. 10/150,183, filed on May 17, 2002; which claimspriority from U.S. Provisional Patent Application Ser. No. 60/361,237,filed on Feb. 28, 2002; which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention is related generally to the field of opticalcomponent alignment in an optical assembly and, more particularly, toarrangements and an associated method for aligning and fixedlysupporting an optical component, as part of an optical assembly, withhigh precision in relation to an optical path.

The prior art appears to be replete with approaches for supportingoptical components in an aligned condition, for example, within anoptical package. While it is admitted that a great number of theseapproaches are at least generally effective, it is submitted in view ofthe discoveries brought to light herein, that these approaches appear toshare a number of heretofore unresolved problems and disadvantages, aswill be further described.

One common approach of the prior art, with respect to optical componentpositioning, relies on supporting an optical component on a “clip”. Thelatter is typically attached to a support surface which is definedwithin the optical package. One, more recent implementation of thisapproach is seen in U.S. Pat. No. 6,184,987, issued to Jang et al(hereinafter, Jang). The clip of Jang supports, for example, an opticalfiber. A metal ferrule, supports the end of the fiber. The clip is laserwelded to a support surface and the ferrule is then laser welded to theclip. Laser hammering is then employed in a way that is intended tocompensate for weld shifts. Since the patent contemplates sub-micronpositioning, the need for further alignment adjustments is virtuallyassured. While various techniques are available in attempting to achieveprecise positioning, Jang utilizes laser hammering, in which additionalwelds are made, thereby attempting to induce strains in strategiclocations to bend the mounting fixture and thereby move the fiber endback into a desired position. Unfortunately, it is not possible toprecisely predict or control hammering induced strains. This method,like any method using laser hammering, therefore, inevitably relies onsome level of trial and error. For this reason, the technique introducedby Jang is likely, at best, to be time consuming and is at leastpotentially unreliable. It is also important to note that laserhammering can result in residual stresses that relax over time, as theunit is subjected to temperature cycling in everyday storage and use.The outcome may be a mounting arrangement that exhibits long-term creepwith an attendant performance degradation over time.

Another approach taken by the prior art also relies on the use of a clipto support the optical component. Unlike the approach exemplified by the'987 patent, however, a positioning arrangement is used both to move theoptical component into a desired position and to then hold the componentin the desired position as the clip is welded in place within theoptical assembly. This approach may be referred to in a generic sense as“direct-clamping.” Generally, the term direct-clamping, as used herein,refers to any arrangement wherein a clamp or holding tool manipulatesthe optical component. In this regard, a clip that is suitable for usein direct-clamping may take on any number of configurations. In one formof direct-clamping, the support clip is at least somewhat spring-like.Unfortunately, however, this implementation is subject to relativelylarge magnitudes of spring-back upon release of the component. Whilespring-back is generally problematic using any form of direct-clamping,it is submitted that weld shift still further exacerbates thespring-back problem since the flexible clip absorbs much of the weldshift in the form of elastic deformation. Release of the flexible clipserves to release the absorbed elastic deformation thereby resulting inmovement of the optical component. In sum, the offending stresses whichproduce spring-back are difficult to avoid, and unless the mounting clipis extremely rigid, small stresses may lead to large shifts of up to3-10 microns (μm). One approach seen in the prior art in an attempt tocope with this is to use calibrated or calculated overextension. Thatis, moving past the desired position prior to release, and/or, inanother approach, by performing laser-hammering after release.Unfortunately, it is submitted that these more traditional approaches atbest are touchy, process-sensitive and potentially time consuming.

Another form of direct-clamping, referred to herein as “hard-clamping”,is specifically intended to overcome the problem of such weld shiftsinducing a corresponding positional shift in the optical component. Atthe same time, this method attempts to cope with the spring-backproblem, described above, particularly complicated through the use of aflexible clip. Accordingly, the positioning arrangement used in ahard-clamping implementation must be capable of maintaining sufficientforce (roughly ten to thirty pounds of force), to rigidly hold theoptical component in place while welding is performed. This methodraises concerns in requiring a bulky, rigid clamp, as well as a rigidcomponent or clip (typically, the part to be mounted consists of solidmachined construction). These structural mandates are imposed for thepurpose of supporting the optical component to resist or overcomeweld-induced forces which tend, in turn, to produce the subjectunpredictable changes in positional relationships. Another concern isintroduced wherein the optical component is of insufficient strength toendure this form of direct-clamping. In this instance, the method may beimplemented by providing a rigid support structure having a mountingplatform with the optical component mounted thereon. The mountingplatform is then itself hard-clamped to resist weld shift.Unfortunately, it is submitted that hard-clamping techniques, in any ofthe described varieties, encounter significant difficulties inattempting to produce reliable positioning (as contemplated herein, to±0.1 μm tolerance). In order to reach the contemplated degree ofprecision, subsequent post-weld hammering or bending is typicallyneeded. In addition to the foregoing concerns, it should be appreciatedthat in any technique using some form of clamp or holder to position theoptic (or its directly supporting platform) before and during thewelding process, the clamping tool must be disengaged at some point.Unclamping unavoidably releases residual forces, thereby causing atleast some undesired spring-back such that this problem remainsunresolved.

As alluded to above, another common approach in the prior art involvespost-weld bending. That is, after initial positioning and welding, aholding clamp is used to bend support members, such as legs, whichsupport the optical component, to move the optical component into thedesired position. Often, the support members are designed specificallyfor quick onset of plastic deformation as bending forces are applied.This approach, however, shares a disadvantage with direct-clamping.Specifically, some level of elastic spring-back will typically followany attempt at precision bending. While spring-back can be compensatedfor somewhat predictably by intentionally overshooting the desiredposition, it is submitted to be extremely difficult to compensate towithin 0.1 μm tolerances. In this regard, one of the attractions oflaser hammering, in contrast to post weld bending and direct-clamping,resides in the fact that the holding tool is disengaged prior to thefine-adjustment steps, so there is no tool removal-induced spring-back.

A more recent approach to the problem of weld shifts is demonstrated byFIG. 4A of Published International Patent Application No. WO 01/18580 byWebjorn et al (hereinafter Webjorn). The subject figure illustrates asupport structure having an elongated main body including a pair of legspositioned proximate to either end. The optical component is describedas being positioned “close” to a front pair of the legs. The main bodyincludes a pair of gripping holes arranged proximate to each of itsends. This structure is used by performing an initial alignment using agripping tool which engages the pair of gripping holes closest to theoptical component. Following this initial alignment, the front pair oflegs is welded. A second alignment step compensates for “post-attachmentshift” by gripping the main body using the pair of gripping holes at itsrear end. The structure is described as allowing a “small positioningcorrection” to compensate for weld shift produced by attachment of thefront legs through moving the rear of the support structure. The rearlegs are then welded and the gripping tool is removed. Of course, a weldshift is also produced upon welding of the rear legs, however, based onthis configuration, the weld shift at the rear of the structure would beexpected to produce a corresponding, but reduced magnitude of shift atthe optical component.

Still considering Webjorn, while the described support structure andtechnique should be generally effective in achieving precisionalignment, it is submitted that important disadvantages accompany itsuse. It is submitted that the very length of the elongated main bodyalong the light path and which is required in order to achieve precisionmovement, already renders the device far too long for many applications.More importantly, any bending or other such distortion, for example, dueto thermal stresses or mounting, in the overall package which houses theWebjorn arrangement will result in reduced optical coupling. It isherein recognized that the length of the main body, even without anincrease therein for purposes of adjustment enhancement, is likely todisadvantageously require an overall package outline that is stiffer andbulkier (and therefore larger and more costly) than would traditionallybe required. While the Webjorn disclosure describes a shorter,two-legged clip, the precision alignment technique is applicable only toa four-legged structure.

At first blush, it may appear that increasing the main body length ofWebjorn and, hence, the separation distance between the front and rearpairs of legs is attended only by advantages in further refiningadjustment precision. Any resultant advantage, however, is atcross-purposes with other objectives, inasmuch as miniaturization is asubstantial motivation in producing many optical assemblies. That is, anincrease in length still further complicates matters with respect topackage bending and outline.

Another recent approach is seen in U.S. Pat. No. 5,833,202 issued toWolfgang. The latter introduces a tripod-like component supportstructure which is intended to be deformable or bendable for positioningadjustments. With respect to precision alignment, however, Wolfgang issubject to weld shift and spring-back effects as a result of itsapparent reliance on direct-clamping, which is described in terms ofmicro-manipulation of the mounted optical component at column 6, lines54-55. Moreover, it is submitted that the sole structure described indetail by Wolfgang, a tripod, is not well-suited for linear stackingalong an optical path for purposes of producing a compact assembly. Inthis regard, it is noted that this disadvantage is shared with Webjornsince the latter requires the use of an elongated main body.

The present invention resolves the foregoing disadvantages and problemswhile providing still further advantages, as will be described.

SUMMARY OF THE INVENTION

As will be described in more detail hereinafter, there is disclosedherein an optical assembly as well as an associated method. The opticalassembly includes a light path and at least one optical component to bepositioned in the light path and further includes one or more supportsurfaces. In one aspect of the present invention, a support arrangementincludes support means for supporting the optical component and having afoot arrangement including at least one foot that is configured forreceiving a direct manipulation with the foot slidingly engaged againstone of the support surfaces such that the direct manipulation of thefoot moves the optical component relative to the light path. In onefeature, the foot includes a manipulation configuration for receivingthe direct manipulation to move the foot slidingly against the supportsurface that it is engaged therewith. In another feature, the supportmeans is configured for moving the optical component along apredetermined path with a selected direct movement of the foot and thepredetermined path at least generally defines a plane that is normal tothe light path.

In another aspect of the present invention, an optical assembly includesa light path and an optical component to be positioned in relation tothe light path. An arrangement forming part of the assembly includessupport means for supporting the optical component relative to the lightpath having at least one foot with (i) a lower surface for at leastinitially engaging a support surface forming part of the opticalassembly, (ii) an upper surface spaced-apart from the lower surface suchthat the foot includes a first thickness therebetween, (iii) and atleast one weld region having a second thickness which is less than thefirst thickness for use in welding the foot to the support surface. Inone feature, the lower surface extends across the weld region and theweld region includes a stepped periphery formed in the upper surface todefine a weldable surface which is spaced from the lower surface by thesecond thickness. In another feature, the stepped periphery isconfigured for receiving the direct manipulation in a way whichslidingly moves the foot against the support surface prior to attachmentof the foot to the support surface.

In still another aspect of the present invention, an optical arrangementincludes a light path and an optical component to be positioned in thelight path. An assembly forms part of the optical arrangement includingsupport means for supporting the optical component and including atleast two feet which are moveable relative to one another for moving theoptical component such that a known relative positional relationshipbetween the feet produces a known position of the optical component, atleast to an approximation. In one feature, the support means isconfigured for moving the optical component along a predetermined pathwith relative movement of the feet

In yet another aspect of the present invention, an optical assemblyincludes a light path and an optical component to be positioned in thelight path. A positioning arrangement within the assembly includessupport means for supporting the optical component and having a footarrangement including at least one foot for use in positioning theoptical component. The foot includes a configuration for use inselectively biasing the foot against a support surface defined withinthe optical assembly in a first way, during a movement mode, which isintended to permit movement of the foot against the support surface andin a second way, during a locked mode, which is intended to lock thefoot against the support surface. In one feature, the locked mode isintended to at least limit lateral movement of the foot duringattachment thereof to the support surface.

In a continuing aspect of the present invention, an optical assemblyincludes a light path and at least one optical component to bepositioned in the light path and further includes one or more supportsurfaces. A support arrangement includes support means for supportingthe optical component having a foot arrangement including at least onefoot defining a footprint for engaging one of the support surfaces. Thefoot is configured for receiving a direct manipulation in a way whichchanges the footprint on the support surface such that the opticalcomponent moves relative to the light path responsive to changes in thefootprint. In one feature, the foot includes at least first and secondengagement positions, at least one of which is configured for receivingthe direct manipulation such that a distance change between theengagement positions changes the footprint which, in turn, producesmovement of the optical component. In another feature, the support meansis configured for moving the optical component by an amount that is lessthan the distance change between the engagement positions.

In a further aspect of the present invention, an optical assemblyincludes a light path and at least one optical component to bepositioned in the light path and further includes one or more supportsurfaces. An arrangement, forming part of the assembly, includes supportmeans for supporting the optical component and a foot arrangementincluding at least one foot that is configured for engaging the supportsurface. The foot defines first and second spaced-apart positions, atleast one of which positions is capable of receiving a directmanipulation to change a spacing distance between the first and secondpositions which thereby causes the foot to react in a way which movesthe optical component relative to the light path.

In another aspect of the present invention, an optical assembly includesa light path and at least one optical component to be positioned in thelight path and further includes at least one support surface. Apositioning arrangement, within the assembly, includes support means forsupporting the optical component and a foot arrangement including atleast one foot for engaging the support surface in a coarse adjustmentmode during which the foot is moved slidingly as a unit against thesupport surface to at least coarsely position the optical component. Thefoot being configured to thereafter receive a direct manipulation whilesupported against the support surface in a fine-adjustment mode and toreact to the direct manipulation in a way which causes a fine-adjustmentmovement of the optical component.

In another aspect of the present invention, an optical assembly includesa light path and at least one optical component to be positioned in thelight path and further includes at least one support surface. A supportassembly, within the optical assembly, includes a support arrangementfor supporting the optical component and being configured for initialattachment to the support surface at least at a first point in a waythat at least potentially produces an attachment shift at the firstpoint which, in turn, produces a positional shift at the opticalcomponent and the support arrangement includes a soft-spring elementconfigured for receiving an external manipulation and a stiff-springelement arranged for producing at least limited movement of the supportarrangement, thereby moving the optical component. The stiff-springelement is arranged for cooperation with the soft-spring element suchthat a selected external manipulation received by the soft-springelement causes the stiff-spring element to react in a way which movesthe support arrangement, thereby moving the optical component in a waythat is intended to compensate for the positional shift produced at theoptical component by the attachment shift. In one feature, the supportmeans includes at least one foot which is attachable to the supportsurface where the first point, soft-spring element and stiff-springelement are formed as part of the foot.

In still another aspect of the present invention, an optical assemblyincludes a light path and at least one optical component to bepositioned in the light path and further includes at least one supportsurface. A configuration, within the optical assembly, includes asupport arrangement for supporting the optical component and beingconfigured for initial, coarse positioning attachment to the supportsurface. The support arrangement includes a manipulation positionconnected to a soft-spring element for responding to an externalfine-positioning manipulation received at the manipulation position anda stiff-spring element arranged for producing at least limited movementof the optical component, and the stiff-spring element is furtherarranged for cooperation with the soft-spring element such that theexternal fine-positioning manipulation is transferred, in an attenuatedmanner, through the soft-spring element to the stiff-spring element tocause the stiff-spring element to react in a way which moves the opticalcomponent for fine-positional adjustment thereof. The manipulationposition is configured for fixed attachment, at least relative to thesupport surface, in a way which is intended to maintain a fine-adjustedposition of the optical component, but which fixed attachment is atleast potentially subject to an attachment shift at the manipulationposition, which attachment shift is attenuated by cooperation of thesoft-spring element and stiff-spring element to reduce movement of theoptical component away from its fine-adjusted position responsive to theattachment shift. In one feature, the initial attachment position, themanipulation position, the soft-spring element and the stiff-springelement are formed as portions of a foot which is engaged against thesupport surface. In a related feature, the foot includes a footprinthaving a shape against the support surface and the foot is configuredfor deforming responsive to the external fine-positioning manipulationin a way which changes the shape of the footprint.

In yet another aspect of the present invention, a system is configuredfor use in producing an optical assembly which itself includes a lightpath and an optical component to be positioned in the light path as partof the optical assembly. The system includes a support surface definedas part of the optical assembly and movement means for providingcontrolled alignment movements using at least one sharp tip. Supportmeans supports the optical component, which support means includes atleast one foot having a lower surface for engaging the support surfaceand an upper surface, opposing the lower surface, that is configured forcooperating with the movement means for receiving a direct manipulation,applied by the sharp tip to the upper surface of the foot, to move thefoot laterally against the support surface to, in turn, move the supportmeans and optical component supported thereby.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention may be understood by reference to the followingdetailed description taken in conjunction with the drawings brieflydescribed below.

FIG. 1 is a diagrammatic, perspective view of an optical assembly,produced in accordance with the present invention, illustrating the useof two highly advantageous support brackets.

FIG. 2 is a diagrammatic, perspective view of a three-hinge supportbracket, produced in accordance with the present invention and shownhere to illustrate details of its structure.

FIG. 3 is a diagrammatic, cross-sectional view of the foot of FIG. 2shown here to illustrate details of its construction and furtherillustrating details of a manipulation tool that is shown hoveringimmediately above the foot.

FIG. 4 is a diagrammatic, perspective view of the bracket of FIGS. 2 and3, shown here to illustrate engagement of the bracket by a pair ofmanipulation tools.

FIG. 5 is a diagrammatic, elevational view of the bracket foot of FIG.3, produced in accordance with the present invention, illustrating onehighly advantageous manner in which the foot is welded to a supportsurface.

FIG. 6 is another diagrammatic, elevational view of the bracket foot ofFIG. 5, illustrating another highly advantageous manner in which thefoot is welded to a support surface using a manipulation tool having analternative configuration.

FIG. 7 is a diagrammatic, perspective view of an alternativeimplementation of the support bracket of the present invention in whichthe support bracket includes a pair of feet, each of which is attachedto a different surface so as to cantilever an optical componentlaterally away from the feet.

FIG. 8 is a diagrammatic, perspective view of another alternativeimplementation of the support bracket of the present invention, shownhere to illustrate details of its structure, including a flexible linkor web member hingedly attached to a pair of feet.

FIG. 9 is a diagrammatic, perspective view of still another alternativeimplementation of the support bracket of the present invention, shownhere to illustrate details of its structure including four hingesarranged within the overall structure.

FIG. 10 is a diagrammatic, perspective view of another implementation ofthe support bracket of the present invention, showing an alternativeform of a four hinge bracket.

FIG. 11 is a diagrammatic, elevational view of one class of supportbracket, produced in accordance with the present invention, shown hereto illustrate its use of three hinges.

FIG. 12 is a diagrammatic, elevational view of another class of supportbracket, produced in accordance with the present invention, shown hereto illustrate its use of four hinges.

FIG. 13 is a diagrammatic, elevational view of still another class ofsupport bracket, produced in accordance with the present invention,shown here to illustrate its use of a flexible link or web member.

FIGS. 14 and 15 are diagrammatic, perspective views which collectivelyillustrate a highly advantageous first exemplary, alternative scheme fordirect foot manipulation in accordance with the present invention.

FIGS. 16 and 17 are diagrammatic, perspective views which collectivelyillustrate a highly advantageous second exemplary, alternative schemefor direct foot manipulation in accordance with the present invention.

FIGS. 18 and 19 are diagrammatic, perspective views which collectivelyillustrate a highly advantageous third exemplary, alternative scheme fordirect foot manipulation in accordance with the present invention.

FIGS. 20 and 21 are diagrammatic, perspective views which collectivelyillustrate a highly advantageous fourth exemplary, alternative schemefor direct foot manipulation in accordance with the present invention.

FIG. 22 is a diagrammatic, perspective view of a support bracket,produced in accordance with the present invention, including highlyadvantageous fine-positioning feet.

FIG. 23 is a diagrammatic, perspective view of the support bracket ofFIG. 22, further illustrating coarse positioning utilizing one or bothof a pair of manipulation tools in accordance with the presentinvention.

FIG. 24 is a still further enlarged diagrammatic, plan view of the footused on the bracket of FIGS. 22 and 23, shown here to illustrate furtherdetails of its structure, particularly related to its highlyadvantageous fine-adjustment capabilities.

FIG. 25 is a diagrammatic, perspective view of the support bracket ofFIG. 22 further illustrating a highly advantageous fine positioning andattachment process using one or both of a pair of manipulation tools inaccordance with the present invention.

FIGS. 26, 27 and 28 are each diagrammatic views, in perspective,illustrating support brackets which resemble support brackets initiallyshown in FIGS. 7-9, respectively, but which further include highlyadvantageous fine-adjustment feet.

FIG. 26 a is a diagrammatic view, in perspective, illustrating a supportbracket which resembles the support bracket of FIG. 27, however, beingconfigured for using non-parallel support surfaces.

FIG. 29 is a diagrammatic, plan view and FIG. 30 is a diagrammatic,perspective view, collectively illustrating a fine-adjust supportbracket, produced in accordance with the present invention andspecifically including fine-adjustment feet which are configured forreceiving rotational or twisting manipulations to move the supportbracket against a support surface with which it is engaged.

FIG. 31 is a diagrammatic, perspective view of a first asymmetricfine-adjust spring-attenuation foot produced in accordance with presentinvention.

FIG. 32 is a diagrammatic, perspective view of a second asymmetricfine-adjust spring-attenuation foot produced in accordance with thepresent invention.

FIG. 33 is a diagrammatic, perspective view of a staged-biasspring-attenuation foot produced in accordance with the presentinvention.

FIG. 34 is a diagrammatic, perspective view of a modified version of thehighly advantageous fine-adjust support bracket of the presentinvention, shown here to illustrate active alignment using transducerswhich manipulate the fine-adjustment tabs or positions of the supportbracket in accordance with the present invention.

FIG. 35 is a diagrammatic, perspective view of a highly advantageousspring-attenuation foot, produced in accordance with the presentinvention, shown here to illustrate details of its structure.

FIGS. 36 and 37 are each diagrammatic, perspective views illustrating atwo-piece implementation of a spring-attenuation foot produced inaccordance with the present invention and shown here to illustratedetails of its structure and assembly.

FIG. 38 is a diagrammatic, plan view of a spring-attenuated footstructure, produced in accordance with the present invention, and shownhere to illustrate details of its highly advantageous configuration.

FIG. 39 is a diagrammatic, perspective view of a spring-attenuatedsupport arrangement, produced in accordance with the present invention,shown here to illustrate details of its highly advantageous structure.

FIG. 40 is a diagrammatic, perspective view of a highly advantageouscomponent support structure, produced in accordance with the presentinvention, illustrating details of its structure, including anarrangement of hinged members supporting an optical mount.

FIG. 41 is a diagrammatic, perspective view of another component supportstructure, produced in accordance with the present invention, shown hereto illustrate details of its structure for use in three-dimensionalfine-positioning wherein the optical component is supported by acylindrical tube.

FIG. 42 is a diagrammatic, perspective view of still another componentsupport structure, produced in accordance with the present invention,illustrating details of its construction including a springboardconfiguration.

FIG. 43 is a diagrammatic, perspective view showing a combinationsupport arrangement which is made up of the spring-attenuation foot ofFIG. 35 supporting the support structure of FIG. 42, thereby providingfor multidimensional fine-adjustment of the position of an opticalcomponent.

FIG. 44 is a diagrammatic, perspective view showing a four-leggedsupport clip configured with highly advantageous spring-attenuationfeet, produced in accordance with the present invention, shown here toillustrate details of its structure.

FIG. 45 is a diagrammatic, perspective view showing a support structure,produced in accordance with the present invention, with an opticalcomponent supported by a compliant block that is in communication withspring-attenuation feet.

FIG. 46 is a diagrammatic, perspective view showing another supportstructure, produced in accordance with the present invention andresembling the support structure shown in FIG. 45, except for its use ofcompliant biasing members in place of spring-attenuation feet.

FIG. 47 is a diagrammatic, perspective view showing still anothersupport structure, produced in accordance with the present invention andresembling the support structure shown in FIG. 45, except for its use ofcoil springs in place of spring-attenuation feet.

FIG. 48 is a diagrammatic, plan view showing an alternativeconfiguration of a spring-attenuation foot, produced in accordance withthe present invention, showing details of its structure, includinggenerally square manipulation recesses.

FIG. 48 a is a diagrammatic, plan view showing the spring-attenuationfoot of FIG. 48, showing its relaxed shape, as well as its deformedfootprint resulting from direct manipulation.

FIG. 49 is a diagrammatic, plan view showing another alternativeconfiguration of a spring-attenuation foot, produced in accordance withthe present invention, showing details of its structure including ahighly advantageous serpentine soft-spring member.

FIG. 50 is a diagrammatic, plan view showing still another alternativeconfiguration of a spring-attenuation foot, produced in accordance withthe present invention, showing details of its structure including ahighly advantageous out-of-plane soft-spring member.

FIG. 51 is a diagrammatic, perspective view showing a modified form of athree-hinge bracket produced in accordance with the present invention.

FIG. 52 is a diagrammatic, plan view showing a spring-attenuated foot,produced in accordance with the present invention, illustrating detailsof its structure.

FIG. 53 is a diagrammatic, perspective view showing a support structure,produced in accordance with the present invention, illustrating detailsof its construction wherein spring-attenuation elements are built intoportions of the structure other than its feet.

FIG. 54 is a diagrammatic, perspective view showing another supportstructure which resembles the structure of FIG. 53, but which includes afour-hinge support arrangement residing between a pair of support posts.

FIG. 55 is a diagrammatic, plan view showing another highly advantageousimplementation of a foot, produced in accordance with the presentinvention, shown here to illustrate an arrangement of hinges and strutswhich provide spring-attenuated fine-adjustment.

FIG. 56 is a diagrammatic, perspective view illustrating oneconfiguration of a system for performing parallel gap resistancespot-welding on a support structure foot in accordance with the presentinvention for purposes of attaching the foot to a support surface.

FIG. 57 is a diagrammatic, perspective view illustrating a modifiedsystem for performing parallel gap resistance spot-welding on a supportstructure foot, in accordance with the present invention, having a slotor gap introduced in the configuration of the foot.

FIG. 58 is a diagrammatic, cross-sectional view, in elevation, of asystem configured for performing resistance spot brazing on a supportstructure foot, in accordance with the present invention, for attachmentof the foot to a support surface.

FIGS. 59 and 60 are diagrammatic, perspective views, of an adhesiveattachment system, produced in accordance with the present invention,illustrating details with regard to adhesively attaching a supportbracket foot to a support surface wherein a lower surface of the footincludes slot-like adhesive recesses.

FIGS. 61 and 62 are diagrammatic, perspective views, of an alternativeadhesive attachment system, produced in accordance with the presentinvention, for adhesively attaching a support structure bracket foot toa support surface wherein a lower surface of the foot includes acircular adhesive recess.

FIG. 63 is a diagrammatic, perspective view of still another alternativeadhesive attachment system, produced in accordance with the presentinvention, for adhesively attaching a support structure bracket foot toa support surface wherein the lower surface of the foot includeswedge-shaped adhesive recesses.

FIG. 64 is a diagrammatic view, in perspective, of an alternativesupport bracket produced in accordance with the present invention andillustrating the use of footless web members that are themselvesattachable to a support surface.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the figures wherein like components are indicated by likereference numbers throughout the various figures, attention isimmediately directed to FIG. 1 which illustrates an optical assemblygenerally indicated by the reference number 10 and produced inaccordance with the present invention. It is noted that the figures arenot to scale, being enlarged for purposes of illustrative clarity.Further, it is to be understood that naming conventions developed withreference to one or more of the figures such as “upper” and “lower” areadopted in this description and the appended claims for descriptivepurposes only and are in no way intended as being limited in view ofvarying device orientations. FIG. 1 is a partial cutaway view of opticalassembly 10 illustrating its structure. In the present example, opticalassembly 10 comprises a transmitter module which is configured formodulating laser light and thereafter injecting the modulated light intoan optical fiber 12. It is to be understood that the present inventionis not limited to use in transmitter modules, but is applicable in anyform of optical module wherein one or more components must be positionedwith a high degree of precision in relation to some optical path.Moreover, it is further to be understood that the present invention isnot limited to positioning optical components. That is, any form ofcomponent may be positioned with precision using the teachings herein,as will be further described.

Still referring to FIG. 1, assembly 10 includes a module base 14 uponwhich is positioned a modulator section 16, a lens support platform 18and a laser section 20. An optical isolator 22 is positioned betweenlens support platform 18 and laser section 20. An electricalinterconnection arrangement 24 is provided for externally electricallyinterfacing the various components contained within the assembly. Lasersection 20 is made up of various components which are diagrammaticallyillustrated and provided to drive a laser chip 26. Modulator section 16includes a surface waveguide assembly 27 that is configured forreceiving light coupled to it from laser 26 in a manner to be described.An output of the modulator is coupled directly to optical fiber 12. Anelectronic assembly 28 receives an information signal coupled into an RFconnector 29 and which is to be modulated onto the laser light. Onehighly advantageous form of optical modulator, which is well-suited foruse herein, is described in copending U.S. patent application Ser. No.09/898,197, filing date Jul. 2, 2001, entitled HYBRIDLY INTEGRATEDOPTICAL MODULATION DEVICES, which is commonly assigned with the presentapplication and is incorporated herein by reference.

Laser section 20, as shown in FIG. 1, supports a first lens arrangement30 while lens support platform 18 supports a second lens arrangement 32.Each of the first and second lens arrangements includes a lens 36 whichis directly supported by selected implementations of a highlyadvantageous bracket that is produced in accordance with the presentinvention and each which is generally indicated by the reference numeral40. A free space precision coupling of light (not shown) emitted bylaser 26 to modulator waveguide 27 is accomplished by adjusting thepositions of lenses 36 supported by the first and second lensarrangements. Remarkably, as will be further described, the presentinvention provides for positioning these lenses with an empiricallyverified precision better than plus or minus 1 μm.

Referring now to FIG. 2 in conjunction with FIG. 1, attention is nowdirected to details with regard to the structure of a firstimplementation of bracket 40. FIG. 2 is a diagrammatic, greatly enlargedperspective view of bracket 40 illustrating details of its highlyadvantageous structure. In particular, this bracket includes a pair offeet 42 including a first foot indicated by the reference number 42 aand a second foot indicated by the reference number 42 b. It is notedthat either of these feet may be referred to generically as foot 42. Thefeet are supported on a support surface 45 which is defined within theoverall optical assembly. As will be further described, there is norequirement to support the feet on a single support surface. Further,while support surface 45 is illustrated as being planar, any suitableconfiguration may be employed for use in supporting the feet such as,for example, a curved support surface which is engaged by acorrespondingly curved foot. These feet are interconnected by first andsecond lengths or web members 46 and 48, respectively. First link 46 ishingedly attached at one end to first foot 42 a along a first hinge axis50, indicated by a dashed line, while second link 48 is hingedlyattached at one end to second foot 42 b along a second hinge axis 52which is indicated by another dashed line. The remaining ends of firstlink 46 and second link 48 are, in turn, hingedly attached to oneanother so as to define a third hinge axis 54 which is indicated bystill another dashed line. First link 46 includes a platform 56 whichdirectly supports lens 36. The latter may be attached to platform 56 inany suitable manner including, but not limited to laser spot-welding,resistance spot-welding, arc welding, soldering or gluing. Moreover, anysuitable configuration of the device supporting platform may be utilizedand tailored so as to suit an individual device that is to be supported.For example, an optical component may be attached to the lower surface(not visible) of platform 56. As previously mentioned, it is alsoimportant to understand that lens 36 is intended as being representativeof a wide range of potential devices that may be supported andpositioned in accordance with the present invention using bracket 40.For example, optical devices which may be supported include, but are notlimited to the ends of optical fibers, filters, mirrors, lenses andbeam-splitters. Non-optical devices which may be supported include, butare not limited to magnetic disk drive heads, micro-apertures,biosensors, sharp electrode tips and electron emitters. For purposes ofclarity, however, subsequent discussions will be limited to the use ofan optical lens in order to provide for a more full appreciation of theadvantages provided by the present invention. It is considered that oneof the ordinary skill in the art may really adapt the teachings providedby these discussions in view of this overall detailed disclosure.

Continuing with a description of bracket 40 of the present inventionwith reference to FIG. 2, aside from a need to configure first link 46in a manner that is suitable to support lens 36, first link 46 as wellas second link 48 may be provided in a wide range of configurations. Inthe present example, second link 48 is made up of first and second legs60 a and 60 b, respectively, each of which is hingedly attached betweensecond foot 42 b and first link 46 by hinges 62 a, 62 b, 62 c and 62 d.First link 46, likewise, includes first and second legs 64 a and 64 b,respectively, each of which is hingedly attached at one end to firstfoot 42 a by hinges 66 a and 66 b. Alternatively, rather than usingspaced-apart leg members (60 a and 60 b for link 48 or 64 a and 64 b forlink 46) and hinges, material may be allowed to remain therebetween inany suitable configuration for purposes such as, but not limited tostiffening. Specific additional details with regard to structuralconsiderations as to the construction of these links, the hinges whichconnect them to one another and to each of the feet will be provided atappropriate points below.

Having at least generally described the structure of support bracket 40of the present invention, attention is now directed to certain aspectsof its operation and use. Specifically, feet 42 a and 42 b are designedto initially slidingly engage support surface 45. These feet aretypically biased against support surface 45 in a highly advantageousmanner that is yet to be described. Of course, positioning of opticalcomponent 36 is accomplished, in part, by moving feet 42 in unisonagainst support surface 45 in any desired direction in order to achieveat least coarse alignment with respect to a light path. That is, thefeet may be moved in unison to move lens 36 along light path 70 and/ortransverse to the light path to move the lens in a desired direction,for example, in coarse positioning relative to the light path. Inaccordance with the present invention, relative movement of the feetoccurs at least directly toward and away from one another, while beingbiased against support surface 45, parallel to a path that is indicatedby a double-headed arrow 72. Relative movement of the feet in thismanner causes lens 36 to move along a predetermined path which isindicated by the reference number 76 and illustrated as an arcuate,dashed line. In the present example, predetermined path 76 isillustrated for movement of foot 42 b towards and away from foot 42 a,while the latter is held stationary. It should be appreciated that thisdescription is in no way intended as being limited as to how the feetare moved towards and away from one another. For example, the feet maybe moved in unison towards and away from one another.

What is important to understand, however, is that for any known relativepositional relationship between the feet, the position of the opticalcomponent is also known, at least to an approximation. The actualposition varies with tolerances such as, for example, the tolerance withwhich the optical component is attached to the bracket. Accordingly, theoptical component may be moved to a predetermined position, within theconstraints of these tolerances, using coordinated movements of feet 42.In and by itself, this capability is considered as being highlyadvantageous. With appropriate control of the positioning tolerances,the optical component may be moved to a desired position, for example,in relation to a light path. This movement ability is advantageous inthe sense of absolute positioning or in the context of active alignment,as will be further described. Moreover, the need for and use of complex,empirically developed look-up tables such as those which are typicallyemployed using laser hammering (see, for example, the aforedescribedJang patent) is essentially avoided. The present invention, in contrastand as should be readily apparent to one of ordinary skill in the art inview of this disclosure, provides for positioning using straight-forwardmathematical relationships. In the present example, having foot 42 aheld in a fixed position, the relationship is based on the equation of acircle of radius R having its origin on hinge axis 50. Alternatively,trigonometric relationships between the feet and the center point of theoptical component may be employed. In any case, it is important to notethe positioning dynamics using bracket 40 of the present invention aresingle-valued. That is, for any known relative position between feet 42,optical component 36 can be at only one, determinable position. As willbe seen, the deterministic positional support bracket of the presentinvention provides remarkable advantages when used in conjunction with afine-adjust foot arrangement which is yet to be described.

In an active optical alignment implementation, the optical component maybe attached to the bracket of the present invention with a somewhatloose or even arbitrarily loose tolerance. That is, the initial positionof optical component, for a given relative foot position, may only beknown roughly as a result of the optical component attachment tolerance.During active alignment, a wide sweep may then be employed to detect“first light”, wherein the light path is found, such that knowing anabsolute position of the lens with respect to the positions of thebracket feet is not required. From that point, the sweeping advantagesof the bracket are brought to the forefront in precision movement of thebracket feet to precisely move the optical component in accordance withthe teachings herein. It should be appreciated that motion of theoptical component will track motion of the feet, caused by directmanipulation thereof, with high precision. This high precision isthought to provide for a positioning tolerance at the optical componentof less than 1 μm in a plane generally transverse to the light path.

While during at least some steps in the course of active positioning,using active optical feedback, absolute positional tolerances are notimportant, smoothness of motion is important, as is repeatability.Repeatability is needed, since even an active search algorithm gets“confused” if foot motion does not correlate in some regular andrepeatable way to optical component position. The bracket of the presentinvention provides just such highly advantageous characteristics withrespect to both smoothness of motion and repeatability of motion.

Turning now to FIGS. 2 and 3, further details will now be provided withregard to the highly advantageous configuration of feet 42 used insupport bracket 40 of the present invention. FIG. 3 is an enlargedcross-sectional view of foot 42 a taken along a line 3-3 in FIG. 2. Itis noted that both feet are identically configured. Moreover, as will beseen, a modified version of bracket 40 may be configured so as toutilize only one foot. Returning to the description of foot 42 a and asbest seen in FIG. 3, this foot includes a lowermost surface 80 which isconfigured to engage support surface 45. In the present example, bothsupport surface 45 as well as lowermost surface 80 include a planarconfiguration. Foot 42 a further includes an uppermost surface 82 whichis spaced-apart from lowermost surface 80 by a thickness t. With regardto the construction of bracket 40, it is appropriate to note at thisjuncture that the bracket may be integrally formed from a sheet materialwhich includes overall thickness t. Foot 42 a further includes amanipulation/weld region 84 defined within upper surface 82 having asurrounding circular peripheral sidewall 86. The latter defines aweldable surface or floor 88 which is spaced inwardly with respect tolowermost surface 80 by a thickness which is less than aforementionedthickness t. As alluded to, region 84 serves a highly advantageoustwofold purpose. Initially, region 84 may be referred to as amanipulation feature for use in moving foot 42 a against support surface45. On the other hand, region 84 may be referred to as a weld region orwelding feature for use in fixedly attaching foot 42 a to supportsurface 45. The dual mode use of region 84 will be described in detailimmediately hereinafter.

Turning now to FIGS. 3 and 4, attention is now directed to the use ofregion 84 as a foot manipulation feature. To that end, region 84 isconfigured for engagement by a foot manipulation tool 90. FIG. 3illustrates manipulation tool 90 positioned just above manipulationfeature 84 of foot 42 a while FIG. 4 illustrates manipulation tool 90engaging each foot to move the feet either in unison or individually,relative to one another.

Referring to FIG. 3, it should be appreciated that manipulation tool 90has been illustrated to the extent that its features are regarded asheretofore unknown. Remaining portions of the manipulation tool, whichare not illustrated, may be configured by one of ordinary skill in theart to cooperate with those features which are illustrated. Inparticular, manipulation tool 90 includes any elongated body 92 defininga distal, manipulation end 94. The latter includes a peripheraldownward-facing biasing surface 96 having a peripheral manipulationshoulder 98 extending outwardly therefrom. The configuration ofmanipulation shoulder 98 engages peripheral sidewall 86 of the foot in away which provides for a predictable controlled value of movementtolerance when the foot is moved in any selected direction using themanipulation tool. Peripheral biasing surface 96 serves in a highlyadvantageous way to engage uppermost surface 82 of the foot in a waywhich applies a biasing force 100, indicated by an arrow, in order tohold the foot against support surface 45 consistent with the foregoingdescription. It is noted that this movement configuration is consideredas providing sweeping advantages over the prior art in and by itself.Applicants are not aware of any prior art foot configuration that issuited for direct manipulation and/or engagement by a manipulation toolfor purposes of indirect movement of a supported component. As will beseen, this configuration provides still further advantages with regardto fixed attachment of the foot to support surface 45.

Still considering movement of feet 42 against support surface 45, it isnoted that any such movement is accompanied by a movement mode value ofbiasing force 100. In this regard, it should be appreciated thatlowermost surface 80 of each foot engages support surface 45 with acoefficient of friction which is selectable at least to some extent bycontrolling factors such as surface finish. The latter cooperates withthe movement mode value of biasing force 100 and in concert with lateralforces applied by foot manipulation tool 90 to provide for precisionlateral adjustments of the position of each foot on the support surfacewhile, at the same time, serving to avoid undesired movements. Forexample, the application of an excessive value of biasing force couldresult in the need for application of lateral movement forces at a levelwhich produces an undesirable stick/slip movement of the foot. Suchstick/slip movement may cause the release of stress, built up in themanipulation tool, such that when the foot does slip from a particularlocation, it moves wildly or unpredictably on support surface 45, forexample, overshooting a target location to which the foot and, hence,the optical component was intended to move. Accordingly, the presentinvention provides for fine positioning of the feet, accomplished in themovement mode, as a result of a balance between the coefficient offriction, the biasing force magnitude and the magnitude of lateralmovement forces applied by the manipulation tool. Other factors whichinfluence this balance include, for example, the area of lowermostsurface 80 of each foot as well as aforementioned surface finish.

Referring to FIGS. 4 and 5, attention is now directed to one highlyadvantageous manner in which feet 42 are fixedly attached to supportsurface 45 in accordance with the present invention. FIG. 5 illustratesmanipulation tool 90 engaging foot 42 a at some point in time followingthe conclusion of the movement mode and after having initiated anattachment mode. In particular, it should be appreciated that theconfiguration of weld region 84 provides for the use of high quality“foot welds” which may be characterized as “lap welds” to the limitedextent that overlapping material sheets are welded to one another. Thealternative terminology of “foot weld” has been coined for use herein inorder to avoid confusion of the highly advantageous weld regionconfiguration and method with prior art terms having potentiallydifferent connotations.

With regard to the use of manipulator tool 90 in the attachment mode,the manipulator tool is configured so as to define a central throughpassage 106, through which a laser beam 108 is directed at weld surface88 to produce a foot weld 110 which symmetrically penetrates the supportregion underlying support surface 45. During the welding process of theattachment mode, biasing force 100 is increased to a value which isintended to essentially eliminate not only lateral movement of the footagainst the support surface during the welding process, but alsomovement of the foot and support surface towards and away from oneanother. That is, an increase in biasing force is contemplatedcommensurate to overcome weld shift forces that may potentially beencountered. To gain at least a general sense for biasing force 100 inthe attachment mode, the biasing force may be considered as being raisedto level at which any manipulator tool induced lateral movement of thefoot would most likely produce a stick/slip motion. However, themanipulator tool may be incapable of exerting sufficient lateral forceto overcome the tractional holding power of the foot so biased againstthe support surface in the attachment mode.

Considering certain aspects of foot weld 110 including its formation inaccordance with the foregoing teachings, the circular symmetry of weldregion 84 not only provides for predictable movement tolerances of eachfoot during the movement mode, but also provides for small weld shiftsin the plane of support surface 45, as compared to weld shifts typicallyseen using an edge weld or end weld. These latter, highly asymmetricwelds tend to “pull” as the weld pool cools, solidifies, and shrinks. Incontrast, as foot weld 110 shrinks on itself, its basic symmetry insuresthat the foot is not dragged in any particular direction. That is,whatever shift which might occur is caused by other factors: examplesmay include random forces due to crystal formation during solidificationof the weld, as well as material non-uniformity due to graininess orimpurities, or laser beam non-uniformities. While the present inventionis certainly not limited to the use of a flat support surface and flatfoot configuration, such flat surfaces make for higher quality footwelds and hence deliver lower positional shift.

High quality foot welds of the present invention are achieved byfollowing a number of guidelines: (1) Surfaces 45 and 80 should be cleanand as flat as possible; (2) these surfaces must be in close contactaround the weld region; (3) the thickness of the foot in the“thinned-out” weld region should be selected so as to permit sufficientlaser-penetration; (4) and the thickness of the foot in the weld regionshould also not be selected so thin as to warp unpredictably as a resultof local heating and/or other weld stresses. With regard to all of theseguidelines, the configuration of weld region 84 is considered tocooperate with the overall configuration of foot 42 in a number ofhighly advantageous ways, as will be described immediately below.

Still discussing foot weld 110 with reference to FIG. 5, it isrecognized that weld shift is largely a function of weld size; largerwelds produced from higher energy laser pulses generally exhibit largershifts than small welds produced from lower energy laser pulses. At thesame time, a thin 2-4 mil plate may be welded with a lower energy laserpulse than a thicker 8-12 mil plate. Consistent therewith, Applicantshave observed smaller weld shifts as a result of welding a 2-4 mil thickfoot. As a competing consideration, however, those skilled in the artgenerally recommend using plates no thinner than about 8-12 mils, sincethin materials such as 2-4 mil plates are generally subject tounpredictable warping and deformation even with low weld energy. Thepresent invention provides a highly advantageous hybrid welding regionconfiguration which provides the advantages of a thin welding materialwith respect to reduced weld shift while, at the same time, providingthe advantages attendant to the use of a thick weld material withrespect to reduction of warpage and distortion. The present inventionaddresses these competing interests by substantially thinning the footin weld region 84 to the 2-4 mil range while the weld region remainssurrounded by material having an 8-12 mil thickness. Of course, it isemphasized that these benefits are produced to at least some extent solong as the weld region is thinner than the surrounding foot material.

In performing the highly advantageous foot weld of the presentinvention, laser beam 108 may be centered in through opening 106 andfocused at weld region 84 in order to exhibit a minimum diameter at theweld region. The weld pool is intended to cover all or nearly all ofthinned out weld region 84, thereby leaving little to no thinned areaafter the weld, as shown in FIG. 5. This implementation serves to avoidwarping: once the weld is made there is no longer any thin materialleft, but the technique at the same time permits the use of lower laserpower, hence achieving a smaller weld shift.

A still more detailed discussion of the advantages accorded to theconfiguration of weld region 84, in combination with the disclosedmethod for producing foot weld 110, will now be provided. With regard tothe second guideline above, it should be appreciated that manipulatortool 90 serves to evenly bias the entire periphery of the weld region offoot 42 against support surface 45. Moreover, the biasing force isessentially as close as possible to the actual weld. These features areconsidered as highly advantageous since, depending on the surfacequality of lowermost surface 80 of the foot and support surface 45,there may be at least some limited spring-back upon release ofmanipulator tool 90, even though bracket 40 is manipulated using itsfeet. That is, micron or even sub-micron roughness or warping of thefeet will relax when a downward pressing force is relieved. If the footis held down in a location somewhat removed from the weld itself, gapsdue to surface roughness or irregularities, previously sandwichedtogether by the manipulation tool force, may relax and open up furtherwhen the biasing force is removed during tool disengagement. The presentinvention is thought to minimize this effect to a great degree since themanipulator is kept as close as is reasonably possible to the weld.Again, the reader is reminded that the weld ideally fills out nearly tothe edge of through-hole. Weld nugget 110, therefore, fills in any gapspresent due to surface irregularity. Since the manipulator tool isnearly on top of the weld, the only actual effect of tool disengagementis thought to be decompressing the hardened weld nugget. To the extentthat the weld nugget does not reach under the manipulator's area ofcontact, there may be some residual spring-back due to nearby gapopenings, but proximity to the weld is thought to reduce such effects.

With regard to the attachment mode of the present invention, apart fromthe advantages it provides in combination with the movement mode, it isconsidered that the attachment mode provides an elegant andstraightforward method, along with the disclosed apparatus, forutilizing clamp forces (i.e., biasing force 100) to directly resist weldshifts. In this highly advantageous configuration, frictional force frommanipulator 90 bearing down upon the foot provides traction whichdirectly resists at least lateral forces generated by the weldingprocess. Because this in-plane resistive force is produced by staticfriction, and not by the manipulator itself, there is no need for ahighly rigid manipulator. This is especially important in miniaturizedapplications where there simply is no room allocatable for ultra-rigidclamps such as are needed in a more traditional prior art “brute force”hard-clamping approach. Recalling the Background Section discussion ofprior art hard-clamping techniques that are intended to resist weldshifts, the prior art is at a disadvantage inasmuch as that prior artapproach generally requires a bulky clamp, as well as a rigid or“blocky” multi-piece lens mount structure. That is, thin flexible clipsor brackets are generally incapable of transmitting 10 to 30 pounds offorce without themselves deforming. The present invention, in contrast,avoids such problems by using direct foot manipulations. As evidence ofthe sweeping advantages of the present invention over the prior art,Applicants have empirically demonstrated reduction of weld shift from3-μm to less than 1 μm by applying only 5 pounds of downward force on afoot weld, using a small and comparatively flimsy tool that concurrentlyallows ample access for other tools and hardware.

Still considering the advantages of the present invention over the priorart, using the support bracket of the present invention having one ormore feet configured for receiving a direct manipulation, the often seenphenomenon of elastic tool release spring-back is likewise essentiallyeliminated since the foot itself is manipulated. That is, the presentinvention avoids the prior art problem of elastic spring-back whichparticularly accompanies prior art direct-clamping using a “spring-like”support clip in which stored forces are at once released by the clipupon release of a manipulator tool.

Referring now to FIG. 6, an alternative manipulator tool is illustratedindicated by the reference number 90′. This latter manipulator tooldiffers from previously described manipulator tool 90 in its use of areplaceable manipulator tip 120 which is received in an overallmanipulator body 122. The manipulator tip defines a central passage 106′that is aligned with passage 106 to permit laser beam 108 to passtherethrough. This highly advantageous configuration of the manipulatortool produces a triple-weld 124 which fuses replaceable manipulator tip120 directly into the weld nugget. Manipulator tip 120 is then left inplace with removal of manipulator tool main body 122. Empiricaldemonstrations reasonably lead to the conclusion that the onlyspring-back effect which accompanies the use of this embodiment isattributable only to the predictable decompression of solid metal in andaround the weld nugget.

Referring to FIG. 7, an alternative implementation of the supportbracket of the present invention is generally indicated by the referencenumber 40′. The latter is similar to previously described bracket 40,sharing its advantages, while providing still further advantages. Onenoteworthy difference in a comparison with previously described bracket40 is seen in that bracket 40′ is configured for utilizing a supportstructure 130 defining a pair of support surfaces 45 a and 45 b that areoffset with respect to one another. Bracket 40′ includes feet 42 a and42 b supported by support surfaces 45 a and 45 b, respectively. Anothernoteworthy difference resides in the fact that optical component 36 issupported to the side of most of bracket 40′ in a cantilevered manner.In doing so, foot 42 b is “upside down” with respect to its orientationshown in FIG. 2. A cantilevered arrangement may be advantageous in viewof physical constraints imposed in a particular use. Moreover, links 46and 48 have been reconfigured in an exemplary manner wherein link 48 ismade up of a solid material plate that is hinged to plate 46 by a pairof hinges. Again, it is to be emphasized that the highly advantageoussupport bracket of the present invention may be configured in anunlimited number of ways, all of which are considered as being withinthe scope of the present invention. For example, the support surfacesmay be further separated laterally such that foot 42 b is in theorientation of FIG. 2. As another example, support surfaces 45 a and 45b are not required to be parallel and may be orthogonal with properconfigurations of feet 42. In the present example, web member 46 isconfigured to provide for direct manipulation access to foot 42 b.

Turning to FIG. 8, another alternative implementation of the supportbracket of the present invention is generally indicated by the referencenumber 140. It is noted that previous implementations may be describedgenerally as having four relatively stiff plates that are hinged to oneanother along three hinge axes. In contrast, bracket 140 includes aflexible link or web member 142 which is hingedly attached between feet42 a and 42 b along hinge axes 50 and 52, respectively, and which issymmetrical with respect to both of the feet including a pair of legs144 arranged symmetrically to either side of optical component 36.Moreover, the latter is attached in a symmetrical manner to a midpointof link 142. In this implementation, with equal movements of the feettowards and/or away from one another, optical component 36 may be movedalong a vertically oriented predetermined path 146. It should beappreciated, as will be further described that optical component 36 maybe mounted and/or the symmetry of link 142 may be modified in ways thatprovide for a nonlinear predetermined path with equal movements of thefeet towards and/or away from one another.

Referring to FIG. 9, still another alternative implementation of thehighly advantageous support bracket of the present invention isgenerally indicated by the reference numeral 150. Bracket 150exemplifies a symmetrical implementation which may be generallycharacterized as having four hinge axes 151 a-d interconnecting fiveplates. Specifically, a support link 152 is hingedly connected betweensymmetrically arranged hinge links 154 and 156. Each hinge link is madeup of a pair of legs 158 having opposing ends, each of which is hingedto one of the feet and to the support link. As will be seen, this basicfour-hinge structure is highly flexible and may be modified inessentially an unlimited number of ways in accordance with the teachingsherein. As one example, the support link may comprise a planar platform(not shown). In the present example, optical component 36 is attached tothe curved support link along opposing side margins. This attachmentscheme is in no way intended as being limiting. Moreover, symmetricalattachment is not required. Like previously described bracket 140,symmetrical configuration of bracket 150 provides for movement ofoptical component 36 along a vertical path in the view of the figure.Other appropriate arrangements may provide, for example, for movementalong an arcuate path.

Directing attention to FIG. 10, yet another alternative implementationof the support bracket of the present invention is generally indicatedby the reference number 160. Bracket 160 is another example of thefour-hinge bracket implementation and is further intended to provide avery rigid support link 152 for supporting an optical component (notshown) within a cavity 162. It is noted, with the exception of bracket160 of FIG. 10, that the highly advantageous brackets described hereinmay be formed at low cost for example by stamping, etching, or cuttingsheet material. These structures (including bracket 160 of FIG. 10) mayalso be fabricated, for example, by EDM machines, thereby producingparts that may be more expensive in terms of relative cost, but may alsobe more rigid and exhibit higher tolerance in certain directions.

Referring to FIGS. 2 and 8-10, it should be mentioned that thestructures of these brackets act as a reducing lever to the extent thatrelative motion of the feet toward and away from one another, forexample, as a result of weld shift, is reduced by a factor which mayrange from 2 to 10 for vertical motion of the optical component. Thefactor that is achieved, of course, depends on the specificimplementation and may be tailored to suit design motivations. Oneinfluencing parameter with regard to the reduction factor is the choiceof angle θ (shown in FIGS. 8 and 9) defined between the feet and hingelinks. It is noted that the structure of FIG. 7 provides a similaradvantage in the context of one modified orientation of the feet andsupport surfaces.

As described above and generally in contrast with the prior art, thepresent invention has adopted an “indirect positioning” approach wherebyan optical component is aligned relative to a light path, for example,by manipulating the feet of a support bracket which, in turn, supportsthe optical component. Having familiarized the reader with a number ofimplementations of support brackets produced in accordance with thepresent invention, a discussion of more detailed design considerationswill now be undertaken.

Initially addressing somewhat broad structural considerations, astructure usable for indirect positioning consists of one or more rigidor flexible support members interconnected by hinges. The purpose of thestructure is twofold: to provide support between the optic and themounting surface during and after positioning and attachment; and tofacilitate well-controlled and well-defined (predictable) positioning ofthe optic by manipulation of the feet during positioning and prior toattachment of the feet. In the discussions immediately hereinafter,specific designs and methods are described which may, at the least, bedesirable to the end of achieving optimized performance by varioussupport arrangements/brackets, as defined by the following attributes:

Well-controlled, predictable motion of the optic along a predeterminedpath, as determined by relative motion of the feet in the plane of themounting surface or surfaces.

In some cases, it may be desirable to design the support structure'skinematics to provide reduction in motion of the optical componentcaused by weld shifts at the feet.

Hinges should be designed to provide ease of rotation about a welldefined axis.

The support structure should be designed so that post-attachment, it issufficiently rigid to withstand forces due to specified shocks andvibrations. For practical use in many applications, the supportstructure of the present invention should be designed to withstandseveral thousand g's and, thereafter, elastically recover a pre-shockposition.

The support structure and method of the present invention is designed tobe compatible with so called “active alignment” methods typicallyrequired in high-grade fiber optics packaging.

Feet should be configured to be easily manipulated using readilyimplemented manipulation tools.

The manipulation tools should be sufficiently rigid to provide for wellcontrolled motion, but not so large and bulky as to compete with eachother or the support bracket for space within the allowed real estatefor a given application.

Foot attachments such as, for example, weld joints should providesufficient strength and rigidity with a minimal amount of weld shift andwarping at the feet, as well as minimize long term creep ortime-dependent positional shift.

Aside from incorporating all of the foregoing features, supportstructures should be manufacturable at reasonable cost, preferably forless than one USD.

(It is noted that all of these attributes are considered as beingreadily achievable in view of the teachings herein.)

Still addressing structural considerations in a broad sense, thetechnique of the present invention (i.e., directly manipulating a footof a support structure, with or without a highly advantageousspring-attenuation feature which is yet to be described), may be appliedin the context of a variety of support structures. For this reason,various classes of support structures will now be described as asupplement to discussions appearing above which are considered asthemselves enabling one of ordinary skill in the art to practice theinvention. These supplemental descriptions take a still more fundamentalapproach than those descriptions which appear above in order to providea conceptual understanding of the operation of the subject supportstructures and to emphasize the very broad range of equivalents whichare considered as within the scope of the present invention.Accordingly, three structures are described that are considered as beinguseful; however, these structures are exemplary in nature and are notintended as limiting. In this regard, the concepts described herein areequally applicable over a wide range of structures that may befabricated based on the same building blocks. That is, rigid or elasticlinks connected by hinges.

Referring to FIG. 11, one class of support structure is showndiagrammatically in FIG. 11, generally indicated by the reference number180, having three hinges 50, 52 and 54 interconnecting two links, 46 and48 and two feet, 42 a and 42 b. It is noted that previously describedsupport 40 of FIG. 2 resides within this class. By moving either of foot42 a or 42 b, optical component 36 moves in a precise arcuate path;coordinated motion of both feet may be used to move the opticalcomponent along a straight path (or any predetermined path) in anydirection within the plane of the figure. The optical component isattached at a point X and is preferentially located on longer link 46,although it may be attached to either link. With foot 42 a stationary,optical component 36 moves along an arcuate path 182 with movement offoot 42 b, as indicated by a double-headed arrow 184. With foot 42 bstationary, optical component 36 moves along an arcuate path 186 withmovement of foot 42 a, as indicated by a double-headed arrow 188. Thedesigner may preferentially choose link lengths, nominal angle at,formed between the links, and a length between hinge axis 50 and point Xsuch that paths 182 and 186 are nearly orthogonal when either foot ismoved alone, as illustrated. As an alternative (not shown), aconfiguration of particular interest and which may be referred to as adwell mechanism, provides very high attenuation along one direction. Interms of another alternative, it should be appreciated that thestructure of FIG. 11, consistent with most if not all support structuresdescribed herein, may be implemented having a single foot while stillachieving a significant number of advantages. For instance, hinge axis50 may be fixedly hinged to any sort of underlying structure in animmovable manner. Movement of foot 42 b is then performed for allalignment purposes.

Referring to FIG. 12, another class of support structure isdiagrammatically illustrated and indicated generally by the referencenumber 200. Structure 200 includes four hinges 151 a-d. Support platform152 is symmetrically supported by a pair of hinged support links 154 and156. An opposing end of each support link is hinged to one of feet 42.It is noted that previously described support 150 of FIG. 9, as well assupport 160 of FIG. 10, fall within this class. By moving either footindividually toward and/or away from the other foot or by moving bothfeet simultaneously towards and/or away from one another, opticalcomponent 36 moves relative to the feet in a precise path 202 that is atleast generally normal to the plane of the feet. It is noted that thisstructure is under-constrained. That is, support link 152 and theoptical component supported thereby are, at least potentially, able torotate regardless of the foot position. In order to minimize parasiticrotations of support link 152, the design should ensure thatsymmetrically arranged hinges have the same rotational stiffness. Forexample, hinge axes 151 a and 151 d should share a first rotationalstiffness while hinge axes 151 b and 151 c should share a secondrotational stiffness. Also, the feet, in this particular embodiment,should remain coplanar. To further reduce the effect of any parasiticrotation, optical component 36 may be spaced from support link 152 suchthat the optical component resides at the centro of the mechanism.Although this latter structure, including well-designed, elastic hinges,does not require this configuration, it reduces optic motion due tolong-term creep that can occur in any structure. As angles β1 and β2approach 90 degrees, it is noted that the out-of-plane (i.e., normal tothe plane of the feet) attenuation becomes arbitrarily high, but thesensitivity of support link 152 to parasitic rotation also increases.Accordingly, one design consideration balances range-of-motion withattenuation.

Referring to FIG. 13, still another class of support structure isdiagrammatically illustrated and indicated generally by the referencenumber 210. Structure 210 includes two hinges 50 and 52 connectingsingle, flexible link 142 between feet 42 a and 42 b. It is noted thatpreviously described support structure 140 of FIG. 8 falls within thisclass. Like structure 200 of FIG. 12, coordinated motion of feet 42, inthe directions indicated by double-headed arrows 184 and 188, movesoptical component 36 along path 202, again normal to the plane of thefeet, with an attenuation determined by the curvature of the flexiblelink. Tighter curvature provides higher attenuation but less range ofmotion. Flexible link 142 comprises a single elastic beam which replacesthe three links and two hinges of the FIG. 11 structure which, for astructure of similar overall size and profile, provides a significantlygreater range of motion of the optic for a corresponding attenuation.Optical component 36 may be located close to the plane of the feet tominimize parasitic rotation caused by any offset of the optic from theexact mid-span of link 142. In this example, optical component 36 isattached to link 142 by a mount 204.

Referring collectively to FIGS. 11-13, despite a diversity in theoutward appearance of these structural classes, there is a shared,highly advantageous feature: the optical component supported thereby maybe manipulated in three degrees of freedom solely by (i) sliding thefeet, relative to each other for a vertical component of motion and/or(ii) moved together in tandem or unison for horizontal motion, wherein aplanar support surface is slidingly engaged by the feet. As a furthershared advantage, kinematic structures produced in accordance with theteachings herein may be configured to attenuate weld shift such that themotion of the optical component is less than the shift at the feet. Atthe same time, the bracket structure and method of the present inventionserves to significantly reduce spring-back stemming from tool release.This reduction may be seen to be at such levels that tool release springback is essentially eliminated.

With regard to optical component placement, one extension (not shown) ofthe previously described kinematic structures is practiced by offsettingthe optical component either along its optic axis or laterally withrespect to the optical axis. The optical component may be cantileveredgenerally along the optical axis so that the positioning structure andthe optic are not coplanar. This implementation is potentially useful inapplications where the optic must be placed very close to anothercomponent such as, for example, a laser diode or another opticalcomponent, or when the support structure is attached to large feet forsome purpose. Fashioning the entire support structure using solid links,that resist structural twisting, prevents such a cantilevered optic fromexhibiting undesired motion such as, for example, “wagging” during footmanipulation.

As another extension of the foregoing teachings, a beam (not shown) maybe used to laterally offset the optical component from any structuresuch that the optic overhangs one foot. This arrangement is useful, forexample, when the optic must be placed laterally as close as possible toother components or to an enclosure wall of the device package. Ofcourse, a beam arrangement may, in combination with lateral offset froma light path, provide offset along the light path. As still anotherextension of the foregoing teachings, two or more kinematic structuresmay be attached to a monolithic object such as, for example, anelongated object to control both location and angle. Elongated objectsinclude, but are not limited to lens arrays or v-groove arrays.

Attention is now directed to specific details with regard to hingedesign. In particular, the support structures disclosed herein utilizetwo types of hinges, both of which may be created by reducing stockthickness, by through-cutting a stitch-like pattern, along a strip thatspans the structure or by any suitable combination thereof. Thethree-hinge structure exemplified by FIG. 11, uses plastic hinges. Thefour-hinge structure, exemplified by FIG. 12, uses elastic hinges. Theflexible member structure, exemplified by FIG. 13, may use eitherplastic or elastic hinges.

Plastic hinges are designed to yield at very small angular displacementsand to produce rotation about a constant point. Ideally, such plastichinges provide unlimited angular displacement for a constant appliedmoment, but due to strain-hardening of most metals, the required momentwill increase with angular deflection and the number of cycles, whichcould restrict structural range-of-motion. Accordingly, plastic hingesshould be designed to be narrow relative to the link or stock materialthickness, while not exceeding the ultimate strength of the materialduring direct foot manipulation. Typically, the use of a metal in anannealed condition is advantageous.

Elastic hinges, also known as flexures, allow the four-hinge structureof FIG. 12 to move in a repeatable way by acting like rotationalsprings. Because the hinges are essentially small beams, the virtualhinge axis of each hinge moves slightly as the links rotate. For thesmall excursions that these structures typically experience, these hingeconfigurations approximate a perfect hinge in a highly advantageousmanner.

Residual stress due to forming and manipulation will cause changes inthe internal stress state of any hinge over the lifetime of the hingestructure: the three-hinge structure of FIG. 11 is kinematically fullyconstrained and insensitive to this creep. The hinge stresses in thefour-hinge structure, however, should remain well below the yield stressof the hinge material to prevent drift of the optical component overtime. In general, any kinematically under-defined structure with plastichinges will not behave well during manipulation, is susceptible tocreep, and is of very limited use for sub-micron alignment. Accordingly,the present invention favors the use of elastic hinges in such astructure.

Optical component support structures are typically required to exhibitresistance to shock and resonant vibration that could causemisalignment. One common vibration specification requires operation of adevice while shaking sinusoidally from 20 to 2000 Hz at 20 g's peak. Thesupport structures of the present invention are generally advantageousin this regard since the first mode of these support structures istypically well above 2 kHz. Also, the support structures of the presentinvention may be fabricated using a large range of materials, typicallymetals 0.005″ to 0.015″ in thickness whereby choosing dimensions tosatisfy vibration testing is a relatively straightforward designconsideration. Structures having a flexible link such as shown in FIG.13, typically have a lower first resonance than those structures withrigid links. The modes of a structure incorporating a flexible link maybe tuned, for example, by appropriate positioning of the lens.

The shock specification for an optoelectronic device typically requiressurviving a haversine pulse with a peak acceleration of up to a fewthousand g's. For the exemplary classes of structures shown in FIGS.11-13, design considerations include:

For the three-hinge structure of FIG. 11, which is fully constrained,the hinges are generally not rotatable responsive to shock. Accordingly,the links between the hinges should be configured to prevent plasticdeformation.

For the four-hinge structure of FIG. 12, which is underconstrained, thehinges themselves should be configured to prevent plastic yielding.Design formulas for flexural hinges which account for such concerns maybe found in the prior art.

For the flexible-link structure of FIG. 13, the two hinges should beconfigured, for example, based on physical size to prevent plasticyielding; as a competing concern, however, if the hinges are too large,additional force will be required to move the feet. As a furtherenhancement, the first resonance of the structure may be tuned byvarying offset of the optical component from the flexible link using anysuitable mounting arrangement.

The feet of all support structures of the present invention should besufficiently large in footprint and sufficiently thick to preventmoments, arising from shock, from causing yielding at attachment pointssuch as, for example, weld edges. Proper mechanical shock design willprovide a structure which may resonate responsive to the initial receiptof the shock force, but will return elastically to its pre-shock alignedposition in view of the teachings herein and in combination with thecapabilities of one having ordinary skill in the art relating tomechanical shock design.

The present invention provides many advantages for the active alignmentmethods used in manufacturing including higher device yield, fasteralignment, and the use of less expensive robots and lasers. Duringactive alignment, either a technician or software observes the couplingof light (or “insertion loss”) through the optical component to informthe motion of the positioning structure. Because only a single feedbackvariable, the optical coupling, is used to control multiple positionvariables, any error between the expected and actual position of theoptic increases the time and complexity of the alignment. The prior artdescribes alignment techniques that seem to rely on minimizing thispositioning error such as exemplified by the Webjorn application,described above. Unfortunately, other techniques, exclusive of Webjornand of which Applicants are aware, require an iterative procedure withmultiple tool engagements, thereby adding time and risk of inaccuracy.The support structures of the present invention, on the other hand, arecompatible with robust, high-yield active alignment techniques. Itshould be emphasized that this is an important advantage at least forthe reason that alignment of optical components in a device is one ofmany production steps, and necessarily occurs toward the end of thedevice manufacturing line where any re-work at such a late stage in theoverall manufacturing process is costly or impractical.

With further regard to manufacturing processes, it is submitted that thesupport structures of the present invention and associated method arecompletely compatible with standard volume manufacturing processes. Thepresent invention contemplates binned or tape-fed structures beingcoarsely positioned within the package by a robotic arm. Amachine-vision system, for example, then guides the tools into positionwith a resolution of a few thousandths of an inch until engaging thefeet of the support structure. The structure, in one technique, iscoarsely manipulated to produce a zig-zag motion at the opticalcomponent during the movement mode until first light is found. At thispoint, active alignment begins using a “peak-find” algorithm. Thislatter step, however, is completely unlike procedures seen in the priorart at least for the reason that a known positional relationship betweenthe feet correlates to a known position of the optical component withinacceptable tolerance limits. Once the position is optimized, themanipulation tool increases clamp force on the feet in the attachmentmode, for example, to a few pounds for positionally affixing the feet,for example, by welding. Still further procedures may then be undertakento finely position the optical component, for example, using a highlyadvantageous foot arrangement which will be described below.

It is to be understood that a variety of alternative features may beprovided on support structure feet to be engaged by appropriatelyconfigured tooling thereby being considered to fall within the scope ofthe present invention as generally encompassing any support structurehaving feet configured for direct manipulation. In the foregoingdescriptions, tool 90 of FIGS. 3-5 and tool 90′ of FIG. 6, fit justinside the weld region. This form of tool includes a central hole orpassage in order to allow clearance for a laser weld beam. The toolmoves the foot by pressing against inner side wall 86 of the weldregion. The same tool concurrently biases the foot downward, applyingbiasing force just around the periphery of the weld region. Advantagesof this scheme include:

Minimized tool liftoff shift caused by warped feet or any otherdeviations from perfect flatness in either the foot or the mountingsurface, since the tool is engaged in close proximity to the weldregion.

Tool engagement requiring no additional features on the foot other thanthose already provided by the weld area and peripheral sidewall.

Referring to FIGS. 14 and 15, attention is directed to a firstexemplary, alternative scheme for direct foot manipulation which isgenerally indicated by the reference number 220. Specifically, holes orrecesses 222 may be provided for engaging a foot 224 (partially shown)away from one or more weld areas 226, a pair of which is shown. As seenin FIG. 15, recesses 222 are formed as through-holes, but this is not arequirement for purposes of positive tool engagement. A footmanipulation end of a manipulation tool 228 includes a pair ofmanipulation pins 230 (FIG. 15) that are configured for engagingrecesses 222. Consistent with previously described implementations,manipulation tool 228 includes a lowermost surface 232 (FIG. 15) that isconfigured for applying biasing force 100 against the foot for operationin the aforedescribed movement and attachment modes. In using thisconfiguration, for example, with laser welding, there is no need to passthe laser beam through a central passage within the tool, since thewelds are made sufficiently away from the body of the tool. Thisapproach provides for the use of relatively smaller holes for both theweld areas and the tool engagement recesses. Moreover, thisconfiguration provides for control of foot angle for affectingstructural twist. That is, manipulation tool 228 may apply a twisting orrotational force to foot 224. Using just this twisting motion,orientation parameters of the optical component may be adjusted inadditional degrees of freedom including, for example, pitch with respectto the light path.

Once initial welds are made in weld regions 226, tool 228 may be removedin order to form welds in recesses 222, if desired, which were initiallyused for engaging the tool. In this regard, such multiple welds mayprovide added strength and stability at no cost in real estate, sincemultiple positions were initially used by the manipulation tool. In viewof this alternative implementation and those yet to be described, itshould be apparent that a wide range of modified, but equivalentarrangements are foreseen including, but not limited to placements andnumbers of attachment and manipulation features.

Turning now to FIGS. 16 and 17 a second exemplary, alternative schemefor direct foot manipulation is generally indicated by the referencenumber 240. In this implementation, a foot 242 is provided having anoutermost periphery 244. A movement end of a manipulation tool 246 isshown hovering over foot 242 for purposes of clarity and consistent withother figures. Tool 246 includes a peripheral tab configuration 248 atits foot engagement end which generally surrounds outermost periphery244 of foot 242 during foot manipulation and holding through applicationof biasing force 100. As an advantage which is shared by all of theseimplementations, foot 242 and tool 246 cooperate for operation duringthe manipulation and attachment modes. In the present example, a pair ofweld pockets or attachment points 249 are provided. It should beappreciated that a single weld feature may be used to provide a stillmore compact configuration of foot 242.

Referring to FIGS. 18 and 19 a third exemplary, alternative scheme fordirect foot manipulation is generally indicated by the reference number260. In this implementation, a manipulation tool 262 is provided havinga pair of hard, sharp tips 264 that engage an upper surface 266 of foot268 by “digging” into the foot material itself. In one form, tips 264may be conical or pyramidal in shape. When engaged, tips 264 displacefoot material to form small divots 270. A pair of weld regions 272 arealso illustrated. In order to insure anticipated operation, materialcomprising surface 266 of foot 268 should be somewhat softer than thetool tip; an annealed foot and carbide tool tip are well-suitedmaterials, although a semi-hard foot steel is acceptable. Moreover,surface 266 and tips 264 are cooperatively configured to provide properoperation in the movement and attachment modes. For example, excessivepenetration of the tips into the foot, as a result of applying biasingforce 100 in the attachment mode, should be avoided so as to prevent“sticking” of the tips in the foot or even penetration through theentire thickness of the foot, which results in loss of biasing force.This implementation offers several advantages in conjunction withadvantages shared with other implementations. Specifically, tool 262 mayengage the foot at any point over a relatively large area, requiringless positional accuracy prior to engagement; additionally, there isessentially no hysteresis present between the tool and the foot duringmanipulation.

Referring to FIGS. 20 and 21, a fourth exemplary, alternative scheme fordirect foot manipulation is generally indicated by the reference number280. In this implementation, manipulation tool 228 of FIG. 15 is usedincluding spaced-apart manipulation pins 230. A directly manipulablefoot 282 is formed including an opposing pair of manipulation notches284 formed in sidewall margins of the foot such that during engagementwith manipulation tool, with application of biasing force 100, movementtolerances are controlled between the manipulation tool and foot.

With regard to manipulation tool design, tool surfaces which applybiasing force 100 may be coated with an anti-friction material such as,for example, Teflon to allow the tool to move smoothly over the footwhile any tolerance gap between the tool boss and foot is traversed. Forexample, with reference to FIG. 3, a tolerance gap is traversed betweenmanipulation shoulder 98 of the manipulation tool and peripheralsidewall 86 of the weld region during engaged movement. While thishysteresis is traversed, higher frictional values between the foot andmounting/support surface ensures that the foot does not move on supportsurface 45. It is emphasized that, with the appropriate choice of tooland foot geometries, the amount of hysteresis is constant and readilyincorporated into an active alignment control scheme. One option, whicheliminates hysteresis, resides in the use of a cone-shaped tool tip (notshown) that completely engages peripheral sidewall 86. The tool andsidewall should be configured in a cooperative manner so as to avoidsticking of the tool for contemplated values of biasing force 100.Appropriate coatings may be applied, for example, to a cone-shaped tooltip in order to further enhance non-stick behavior.

With regard to precision control of foot motion, surface anomalies atthe interface between the foot and the mounting surface may cause smallvariations in frictional force. If the tool and motion system areflexible and springy in the manner of some prior art arrangements,bending of the tool and motion system is produced due to stickingaction. This action can then randomly unleash large and unpredictablemovements which makes precision control difficult. Such motion isclassically presented any time a changing force is applied to aspring-like element connected in series to a friction element. Thepresent invention avoids such unpredictable stick-slip behavior by usingflexure-based motion stages with a stiffness of at least 1 Newton per μmand tools that are at least ten times as stiff. Also, it has been found,as an example, that the friction at the manipulation tool/supportsurface interface is very constant when clean steel with a surfacefinish of 8 to 32 microinches is used. Empirical results havedemonstrated consistent incremental foot motion of 0.1 μm using anarrangement similar to that described with regard to FIGS. 3-5.

The support structures of the present invention may be fabricated usingany or a combination of techniques either presently known or yet to bedeveloped. The former includes, for example, PCM (photochemicalmachining or chemical etch), EDM (electro-discharge machining), lasercutting, stamping/forming, or electroforming. PCM is presently the leastexpensive method for high volume (tens of cents per part) and producescompletely stress-free parts, but it requires a minimum feature sizethat is approximately stock thickness, which limits the amount ofminiaturization possible. Wire EDM can produce features as small as0.003 inch slot width in any thickness material, and the sheet stock maybe stacked to cut 50 to 100 structures in one pass of the wire. Lasercutting can produce arbitrarily small features and advanced shops canproduce etched-down areas, but the per-part cost does not drop withquantity. It is submitted that electroforming can be economical inquantity, but restricts the choice of material. It is further submittedthat stamping is not generally preferred, since it tends to distortparts with a high aspect ratio.

Turning to FIG. 22, a highly advantageous support bracket, produced inaccordance with the present invention, is generally indicated by thereference number 300. It is noted that support bracket 300 fallsgenerally within the aforedescribed three-hinge class such as previouslyillustrated, for example, by FIGS. 2 and 11. To the extent that thisbracket is essentially identical to brackets already described,descriptions will not be repeated for purposes of brevity and the readeris referred to those descriptions which appear above. The way in whichbracket 300 does differ from those brackets previously describedcomprises a highly advantageous improvement which provides still furtheradvantages over those already sweeping advantages described above withrespect to the prior art. In particular, bracket 300 includes highlyadvantageous fine positioning feet 302 (which may be referred toindividually as foot 302). As will be further described, each foot 302includes a soft-spring stiff-spring configuration, which may also bereferred to as a spring-attenuation configuration, having a finepositioning adjustment capability which is highly advantageous,particularly with regard to positional compensation for attachmentshifts.

Still referring to FIG. 22, it should be appreciated that bracket 300,with its fine positioning feet, is readily adaptable for using supportsurface configurations in the manner described above with regard toother support brackets of the present invention. For example, the feetmay be supported on different surfaces, by curved surfaces and/or bysurfaces that are non-parallel with respect to one another.

Turning to FIG. 23 in conjunction with FIG. 22, for purposes of thepresent example, bracket 300 will be described as being supported bysupport surface 45. Initially, it is noted that each foot 302 includes alowermost surface (not visible) which is configured for slidingengagement against support surface 45. As in those foot implementationsdescribed above, each foot 302 is configured for movement in a movementmode, in a plane along x and z axis indicated by crossbar arrowheadlines, as well as for being held against the support surface in a waythat is intended to prevent movement in an attachment mode, based on thevalue of aforedescribed biasing force 100. With regard to theimplementation of the movement and attachment modes as bearing on thespecific configuration of foot 302, the reader is referred todiscussions which appear above.

Referring to FIG. 24 in conjunction with FIGS. 22 and 23, the formerfigure is a still further enlarged view of foot 302 shown here forillustrating details of its structure. Considering the specificstructure of fine-adjust foot 302, each foot includes an innermanipulation/attachment position 304 and an outermanipulation/attachment position 306, either of which may be referred toas a manipulation position or as an attachment position, depending onthe particular context of the discussion, since these positions serve indual roles. In one implementation, these attachment positions or regionsmay be configured in a manner that is consistent with attachment region84, described in detail above. As will be further described, foot 302 issymmetrically arranged on either side of an axis of symmetry 307. Theuse of bracket 300 is essentially identical to the use of bracket 40described above to the extent that inner positions 304 may serve in thecapacity of previously described attachment regions 84 (see FIGS. 2through 5). Specifically, optical component 36 may at least be coarselypositioned using inner manipulation positions 304. To that end, FIG. 23illustrates one manipulation tool 90 engaging one of the innermanipulation positions while another manipulation tool 90 is shownhovering immediately above the other inner manipulation position. Uponengaging both manipulation tools with the pair of inner manipulationpositions, “coarse” adjustment of bracket 300 may be performed so as toat least generally align optical component 36 with respect to light path70 and along indicated x, y and z axes. In this regard, it should beappreciated that the term coarse is used as being descriptive of aninitial alignment step. The use of bracket 300 in this manner,remarkably, has been found to be capable of achieving an alignmenttolerance of approximately 1 μm using the teachings above, particularlywith regard to employment of the movement mode and attachment mode.Moreover, as also described above, there is always some potential forthe production of an attachment shift, responsive to attachment of innerpositions 304 to support surface 45, for example, using laser welding,spot-welding, adhesives or any other suitable attachment method. As willbe seen, foot 302 is configured in a highly advantageous and heretoforeunseen manner with regard to attachment shift compensation.

Referring collectively to FIGS. 22 through 24, but with particularreference to FIG. 24, it is appropriate at this juncture to continue thedescription of the structure of fine-adjust feet 302. Each foot includesa pair of stiff beams 310 and a pair of arcuate-shaped soft beams 312.Stiff beams 310 extend at least generally from inner position 304outwardly having an outer end that is proximate to a pair of hingingpositions 314 on the foot, arranged along one of hinging axes 50 or 52.Accordingly, the outward ends of beams 310 move at least generally withthe hinging positions at which links 46 and 48 of the support bracket300 are hingedly attached to the respective feet. Outer position 306 ofeach foot 302 is formed within a tab 320 that is connected to and incommunication with the outward ends of stiff beams 310, and thereby thehinging positions, through arcuate-shaped soft beams 312. As will bedescribed in detail, the soft and stiff beams serve as soft and stiffspring-like or compliant elements, respectively, for the purpose offine-adjustment of the position of optical component 36.

Still describing spring-attenuation foot 302 of the present invention,attention is now directed to the specific way in which thisfine-adjustment foot is installed in order to accomplish finepositioning. Having accomplished coarse positioning relative to a lightpath, for example, in the manner illustrated by FIG. 23 whereinmanipulation tools 90 at least achieve an initial alignment of anoptical component supported by the feet, inner positions 304 are fixedlyattached to support surface 45. The attachment may be performed in anysuitable manner either presently available or yet to be developed suchas, for example, laser welding or through the use of adhesives. Asmentioned previously, some degree of attachment shift will generallyaccompany any of these attachment techniques. As will be furtherdescribed, the present invention contemplates the use of spot-weldingfor purposes of achieving this attachment in a highly advantageous andunforeseen manner.

Referring to FIGS. 24 and 25, a fine-adjustment procedure is thenemployed after having attached inner positions 304 of feet 302 tosupport surface 45. In order to accomplish this task, manipulation tools90 are moved to engage outer positions 306 of the feet as shown in FIG.25. Manipulation of the outer foot positions then proceeds in a highlyadvantageous manner by deforming the foot against support surface 45 bymoving engaged manipulator 90 at least along the x arrowhead line. It isimportant to understand that these outer, fine-adjustment positions maybe manipulated either individually, or concurrently within the contextof an overall fine-adjustment procedure. With regard to concurrentmanipulation, outer positions 306 of foot 302 at either end of bracket300 may be moved simultaneously in different directions or in paralleldirections.

During fine-adjust manipulation of outer position 306 of each footagainst attached inner position 304, the structure of foot 302 serves ina highly advantageous manner. In particular, stiff beam elements 310have a relatively high stiffness K in relation to narrower, arcuate softbeam elements 312 having a stiffness k. Accordingly, manipulation offoot 302 slidingly against support surface 45 using outer position 306serves to apply biasing forces to hinging positions 314 (FIG. 24)defined on the foot. Motion of the hinging positions is limited,however, by the higher stiffness of stiff beam elements 310. In thisway, the motion of each foot is favorably attenuated by the factork/(K+k). In and by itself, this configuration is considered to be highlyadvantageous. Stated in a slightly different way, it is important tounderstand that foot 302, in a relaxed state, defines a footprint onsupport surface 45. This footprint, with manipulation of outer position306, changes or deforms in way which serves to move hinging positions314 at least generally along arcuate paths 322 thereby pivoting aroundattached inner position 304. Consequently, links 46 and 48 move so as tomove optical component 36 in a highly advantageous spring-attenuatedmanner. In terms of modifications, the present invention considers anyconfiguration as within its scope wherein changes in a footprintconfiguration or foot shape result in movement of optical component 36.In this regard, it should be appreciated that hinging positions 314 maybe located at any suitable locations within the overall foot structure.Moreover, there is no requirement for a symmetrical foot arrangement,even though such an arrangement may serve as an enhancement in terms ofpredictability of optical component movement in view of contemplatedfoot motion.

It should be appreciated that changing the distance between positions304 and 306 of each foot in any direction, while the foot is biasedagainst support surface 45, is accompanied by movement of opticalcomponent 36. Movement of positions 304 and 306 of each foot toward andaway from one another along line of symmetry 307 (the x axis in FIGS. 23and 25) causes optical component 36 to move in an attenuated manneralong a predetermined path in the vertically oriented xy plane (see path76 of FIG. 2). Movements of outer position 306 having a component thatis orthogonal to line of symmetry 307 serve to rotate both hingingpositions 314 about attached inner position 304 in a manner whichinfluences orientation parameters of optical component 36 in addition toits position in the xy plane.

Still referring to FIGS. 24 and 25, it is important to understand thatbracket 300 is advantageous in respects beyond its already highlyadvantageous precision positioning capabilities. As one compellingexample, horizontal weld shifts at outer attachment positions 306 resultin correspondingly smaller shifts in stiff beam or spring elements 310.This translates to smaller shifts in the position of optical component36. Likewise, vertical weld shifts at outer attachment positions 306 arealso attenuated or reduced at the optical component, since such a weldshift must twist the foot structure about the inner attachment position304 in order to shift the optical component. That is, the moment armbetween hinge axis 50 (or 52) and inner position 304 of each foot isshort as compared to the moment arm between inner position 304 and outerposition 306. As will be further discussed, hinge axis 50 (or 52)essentially bisects inner position 304 of each foot such that the momentarm between the hinge axis and inner position is thought to be as smallas is realistically possible. This feature, in and by itself, isconsidered to be highly advantageous.

It should be appreciated that, where the foot of the present inventionis attached to support surface 45 at multiple attachment points, forexample, by replacing inner attachment position 304 with two or moreattachment points in the manner illustrated by FIGS. 14-21, the multipleattachment points cooperate in a manner which defines a pivot point orpivot region that is arranged between the attachment points.Accordingly, motion of hinging positions, as well as general deformationcharacteristics of the fine-adjust foot of the present invention, may becharacterized as pivoting about the defined pivot point or,alternatively, about a pivot region.

While “soft-spring stiff-spring attenuation”, which may be referred toherein as “spring-attenuation,” is known in the field of mechanicalengineering of precision instruments, it is important to understand thatthe prior art, to Applicant's knowledge, is entirely devoid of anyapplications wherein this principle has been used specifically toattenuate weld shifts in optical component mounting applications. Forexample, in conventional instruments, spring leverage is used toattenuate motion of a positioning screw to achieve finer positioningresolution than that of the screw. The present invention, in contrast,is considered to apply this principle in a heretofore unknown and highlyadvantageous manner which is neither trivial nor obvious. In doing so,it is further considered that sweeping and, in many instances,empirically verified advantages have been provided over thestate-of-the-art, as will be further addressed.

FIGS. 26, 27 and 28 illustrate support brackets which resemble supportbrackets initially shown and described in FIGS. 7-9, respectively, butwhich further include fine-adjust feet 42. These modified supportbrackets are denoted by overall reference numbers taken from FIGS. 7-9,but having an additional prime (′) mark appended to the originalreference number. It should be appreciated that these modified supportbrackets share all of the advantages of their counterpart, unmodifiedbrackets while further providing the advantages described with regard tofine-adjust foot 42, as described.

FIG. 26 a illustrates a support bracket, generally designated by thereference number 40′″ and which resembles support brackets 40′ of FIG. 7(using directly manipulable feet) and 40″ of FIG. 26 (using springattenuation, directly manipulable feet), thereby sharing theiradvantages. Bracket 40′″, however, is supported by a support structure130′ which includes non-parallel support surfaces 330 and 332. In thepresent example, support surfaces 330 and 332 are orthogonal withrespect to one another, but it is to be understood that this is not arequirement such that any suitable angle may be formed by theintersection of the two surfaces.

With regard to the bipod or dual foot support brackets of the presentinvention described throughout this disclosure, it is worthwhile to notethat these support brackets are compact with respect to the opticalaxis, thereby providing for compact stackability of multiplearrangements along the optical axis, in sharp contrast to many prior artarrangement such as, for example, Wolfgang and Webjorn, described above.

FIGS. 29 and 30 illustrate a fine-adjust support bracket, produced inaccordance with the present invention and generally indicated by thereference number 350. Bracket 350 is generally configured in the mannerof bracket 140′ of FIG. 27 and is shown supporting an optical fiber 352(only partially shown) having an input face 354. Further, bracket 350includes fine-adjust feet 356 which are generally similar to foot 302 ofFIG. 24 and are specifically configured for cooperating with a dual tipmanipulation tool, which may resemble the manipulation tool shown inFIGS. 14 and 15, in order to produce rotation or twisting of the feet asthey are biased against support surface 45 during the initial coarseadjustment procedure. In the present example, feet 356 are configuredfor rotation using a pair of manipulation apertures 360. Furtherexamples of manipulation tools and foot configurations which enable theapplication of such rotational forces are given in FIGS. 16 through 21,in the instance of a foot which is not configured for spring-attenuatedfine-adjustment. In this regard, it is considered that one of ordinaryskill in the art may readily configure a spring-attenuatedfine-adjustment foot for rotational manipulation in view of this overalldisclosure.

Still referring to FIGS. 29 and 30, bracket 350 is illustrated afterhaving been fixedly attached to support surface 45 using its innerattachment positions 304. As a result of equal rotational forces appliedto the feet, link 142 is resiliently deformed in a way which moves inputface 354 of the optical fiber along a vertically oriented path 358, asseen in FIG. 30. By moving feet 356, either in unison or independently,orientation parameters of input face 354 such as, for example, pitch maybe influenced in a selected manner. It is to be understood that thepositional orientation illustrated in FIGS. 29 and 30 has beenaccomplished through the attachment of only inner positions 304 tosupport surface 45. Accordingly, a fine-adjustment step may then beperformed consistent with the foregoing descriptions and illustrationsusing the highly advantageous fine-adjust foot of the present invention.That is, a manipulation tool may be used to engage outer foot positions306 whereby to influence the orientation of input face 354 in a highlycontrolled manner with respect to certain orientation parameters. Forexample, pitch of the input face may be influenced by moving one or bothof outer foot manipulation positions 306 laterally (for example, alongthe axis of optical fiber 352) and fine positioning movement alongpredetermined path 358 may be accomplished by moving both positions 306in a particular way. With regard to these figures, it should beappreciated that orientation changes resulting from positioningmanipulation have been exaggerated for purposes of illustrative clarity.

Although the configuration of the fine-adjust spring-attenuation foot ofthe present invention has, thus far, been illustrated as having asymmetrical configuration, it is to be understood that this is not arequirement. As a first example, FIG. 31 illustrates a first asymmetricfine-adjust spring-attenuation foot which is generally indicated by thereference number 380. Foot 380 includes a first manipulation/attachmentlocation 382 and a second manipulation/attachment location 384. Firstlocation 382 is connected to a main tab 386 of the foot via ahigh-stiffness stage 388 while second location 384 is connected to maintab 386 via a low-stiffness stage 390. Main tab 386 may be attached tothe remainder of an overall support structure, for example, usinghinges. In operational use, coarse positioning may be accomplished usingfirst manipulation location 382. Thereafter, location 382 may be fixedlyattached or attachments may be made proximate to location 382, servingto at least generally fix its location. Fine-adjustment then proceedsusing second location 384 by moving it in any direction while biasedagainst a support surface (not shown). As in all examples herein, wherea foot is moved against a support surface, the use of the aforedescribedmovement and attachment modes are useful.

Turning to FIG. 32, a second asymmetric spring-attenuation fine-adjustfoot is generally indicated by the reference number 400. Foot 400includes a first manipulation/attachment location 402 and a secondmanipulation/attachment position 404. First location 402 is connected tomain tab 386 of the foot using a high-stiffness stage 406 while secondlocation 404 is connected to main tab 386 using a low-stiffness stage408. During operational use, coarse positioning may be accomplishedusing first manipulation location 402. Thereafter, location 402 may befixedly attached (or attachments may be made proximate to location 402,serving to at least generally fix its location). Fine-adjustment thenproceeds using second location 404 by moving it in any direction whilebiased against a support surface (not shown).

FIG. 33 illustrates a staged-bias spring-attenuation foot produced inaccordance with the present invention and generally indicated by thereference number 420. Foot 420 includes main tab 386 within an overallstructure of three or more manipulation/attachment positions. In thepresent example, three manipulation/attachment positions are shown,indicated by the reference numbers 422, 424 and 426. These positions areinterconnected by an overall beam structure 428. In use, coarsemanipulation is first employed and innermost position 422 is fixedlyattached. Second position 424 is then manipulated with a first stiffnessin a first fine-adjustment step. Second position 424 is then fixedlylocated in a suitable manner. Thereafter, third position 426 ismanipulated with a second, lower stiffness in a second fine positioningstep. In this way, any number of progressively lighter stiffness stagesmay be cascaded, for example, to provide progressively finer adjustmentstages.

Referring to FIG. 34, a modified version of the highly advantageousfine-adjust support bracket of the present invention is generallyindicated by the reference number 430. Bracket 430 falls generallywithin the three-hinge class described above with reference numbersapplied accordingly. Support bracket 430 differs, however, in having anouter tab 432 provided in place of outer manipulation/attachmentposition 306 (see, for example, FIG. 22). Outer tab 432 further supportsa manipulation post 434 which is arranged for movement using in-situtransducers 436. In this regard, it should be appreciated that outertabs 432 are not intended to be fixedly attached to a support surface,but provide for continuous adjustment of the position of opticalcomponent 36, even after having fixedly attached inner positions 304.Transducers 436 may comprise, for example, a piezo crystal arrangementor some other suitable form of transducer that includes a transducerfoot 438 that is fixedly attached to support surface 45 in a suitablemanner while an opposing, movement end of the transducer is attached tomanipulation post 434. In such an implementation, electronic controlsmay be used to actively maintain the position of the optic.

A number of alternative implementations will now be described withreference to FIGS. 35-55, each implementation employs spring-attenuationfor the purposes of fine positioning while further serving to attenuateattachment shift. In all of these alternative implementations,attachment shifts are spring-attenuated in one or more spatialdimensions. Mechanical components comprising the stiff-spring elementsare denoted as K while elements comprising the soft-spring elements aredenoted as k. Any of the described structures may be fixedly attached toa mounting surface in any suitable manner such as, for example, bywelding, adhesive bonding or any of the other attachment methodsdescribed in this overall disclosure. In the instance of supporting anoptical component, the mounting surface is understood to be rigidlyattached to the walls or base of a photonics module.

Referring specifically to FIG. 35, a spring-attenuation foot is suitedfor positioning an optical component (not shown) in two dimensions andis generally indicated by the reference number 450. It is noted thatfoot 450 is generally related to spring-attenuation feet described abovesuch as, for example, foot 302 of FIG. 25. Foot 450 includes first andsecond engagement and/or attachment positions 452 and 454, respectively,formed in surrounding tabs A and B. The tabs are interconnected by softand stiff-spring elements k and K, respectively, which are alsoconnected to a main tab 456. The latter defines an attachment well 458for supporting an optical component (not shown). Attachment well 458 mayreceive a support post (not shown) which, in turn, supports an opticalcomponent (not shown). It is to be understood that attachment well 458is not required and that main tab 456 may be used in any suitable way solong as the component being positioned is supported by the main tab insome manner.

Using foot 450, two-dimensional coarse-positioning is accomplished bysliding the entire structure into a desired position on mounting surface45 and then attaching tab A thereto. Any positional shifts occurringduring this attachment are compensated for by adjusting the position oftab B along x and y axes to fine-position a supported component usingspring-attenuation. Further, as described above, any attachment shiftwhich does occur upon fixedly attaching tab B to the support surface isadvantageously attenuated at main tab 456. For example, moving tab Balong the x-axis fine-positions a supported component along the x-axiswhile moving tab B along the y-axis rotates the structure about tab A,which allows the supported component to be, for example, pitchedrelative to a vertical plane (not shown) extending through the x axis.It is noted that thin, flexible beams (k) connecting tab B to the restof the structure are made to allow spring-attenuated motion in both xand y. Thus, spring-attenuated fine-positioning and fastening in the xyplane is achieved by sliding tab B into the desired position on themounting surface, and then fixing tab B to the mounting surface. Stillfurther details will be provided below with regard to the use of thisstructure for fine positioning.

Now directing attention to FIGS. 36 and 37, a spring-attenuation footstructure, that is functionally similar to those described above, isgenerally indicated by the reference number 460. Foot 460, however, is atwo-piece implementation including a base portion 462 which engagessupport surface 45 and an upper portion 464. The latter defines tab Bwhile base portion 462 includes tab A. Positioning upper portion 464 ontop of base portion 462, as shown in FIG. 37, advantageously allows thefoot to take up less width along the y axis. Two-dimensionalcoarse-positioning is accomplished by moving base portion 462 slidinglyagainst mounting surface 45 and, thereafter, attaching tab A to themounting surface, for example, using a base portion attachment region466. Tabs C and D on upper portion 464 are then attached, for example,by welding or other suitable techniques, to base portion 462 to form theassembled structure shown in FIG. 37. Spring-attenuated post-weldadjustment is then achieved at least in the y direction, and potentiallyin the xy plane, by sliding tab B around on top of tab A using an upperportion manipulation/attachment region 468, and then welding tab B totab A, for example, at region 468. This movement and subsequentattachment may be accomplished using the movement and attachment modestaught in detail above. It is of interest to note that, in the assemblyof FIG. 37, soft-spring members k sit directly above and slidinglyagainst stiff-spring members K, lending to a very compactimplementation. It is contemplated that this overall assembly may befabricated as a single part, with part of the structure folded ontoitself (not shown).

FIG. 38 illustrates another spring-attenuated foot structure, in a planview, generally indicated by the reference number 480 for accomplishingfine positioning. A support tab 482 may support an optical component(not shown), for example, on a post (not shown) having an end receivedin a support well 484 or some support structure hingedly attached to tab482. Soft-spring elements, k, are indicated, as well as stiff-springelements, K. It is noted that the upper surface of structure 480 isdiagonally shaded for clarity while manipulation/attachment positionshave opposing diagonal shading. Using foot 480, coarse-positioning isaccomplished by sliding the entire foot structure into the desiredposition on a planar mounting surface (not shown). Thereafter,manipulation/attachment tabs A and B are attached, for example, bywelding to the mounting surface. Spring-attenuated post-weld correctionin two dimensions is achieved thereafter by moving tabs C and D alongthe x and y axes, respectively.

It is considered that foot 480 is completely unlike the prior art atleast for the reason that it exhibits attenuation of attachment shiftsrather than merely providing fine positioning of a component. Finepositioning mechanisms are known in the prior art as described, forexample, in Flexures by Stuart T. Smith, but are expressly limited tofine positioning. In this regard, the teachings of the present inventionare considered to surpass the state-of-the-art in a way that is neithertrivial nor obvious by providing for precise, permanent fine-positioningin combination with additional and heretofore unseen capabilities formaintaining an established or desired position through attenuatingattachment shifts.

Turning to FIG. 39, a spring-attenuated support arrangement, produced inaccordance with the present invention, is generally indicated by thereference number 490. Support arrangement 490 is supported in agenerally vertical plane by a support structure 492 defining a supportsurface 494. Support arrangement 490 includes manipulation/attachmenttabs A-C and a support section 496 defining an aperture configured forreceiving, as an example, an optical component. The tabs and supportsection 496 are interconnected by an arrangement of stiff, K, and soft,k, spring elements, as indicated. In this regard, it should beappreciated that this support arrangement may be modified in anunlimited number of ways in view of this disclosure. Positioning ofsupport section 496 is accomplished in two dimensions by firstcoarse-positioning support arrangement 490 slidingly against surface494. Thereafter, manipulation/attachment tabs A and B are attached tosurface 494. Post-attachment adjustment in two dimensions is performedby moving a single tab C slidingly against support surface 494 and thenattaching tab C to surface 494. It is noted that arcuate flexuralelement k, joining tab C to support section 496, allows relative motionof tab C with respect to the optic in both x- and y-directions. Hence,this single flexural element, in conjunction with the two stiffer notchspring elements K, provides for spring-attenuation of any attachmentshift at support section 496 of any attachment shift arising uponattachment of tab C. The present example serves to illustrate thatsupport surfaces may be arranged in many different ways while stillremaining within the scope of the present invention in view of thisoverall disclosure.

FIG. 40 shows a component support structure produced in accordance withthe present invention and generally indicated by the reference number500. Coarse positioning in the xz plane is accomplished by sliding theentire structure into the desired position on a planar mounting surface(not shown) and then attaching tabs A and B to the mounting surface. Forpurposes of fine positioning, manipulation/attachment tabs C and D areslidingly engagable against support posts 502. An arrangement of hingedmembers extends between tabs C and D including a pair of hinged postseach of which is indicated by the reference number 506, and all of whichcooperatively support an optical mount 508 defining a device receivingaperture 510. Each hinge post is attached at one end to either hingeaxis 512 or 514 while the opposing end of each hinge post is hingedlyattached by a stiff notch spring to a base 516 that is common to supportposts 502. The upper ends of hinge posts 506 are fine-positioned(spring-attenuated) along the x-axis using spring-attenuation. Hinges517 and 518 function individually as structural kinematic hinges, andcollectively as a portion of the stiff-spring. The remainder of thestiff-spring stiffness is generated by hinges 519. Eachspring-attenuation arrangement includes a U-shaped element indicated assoft-spring elements k. Fine positioning is accomplished by moving tabsC and D along the x-axis slidingly against upper surfaces of supportposts 502. These tabs are then affixed in a suitable manner wherein thespring-attenuation arrangements provide highly advantageous attachmentshift attenuation. This structure may be formed by any suitable methodincluding, for example, by EDM.

Still referring to FIG. 40, it should be appreciated that the exemplarysupport structure between hinge axes 512 and 514 is representative ofthe aforedescribed four-hinge structure and is produced in accordancewith teachings above related thereto. Further, other structural classesdescribed above such as, for example, the three-hinge or flexible webclasses may be employed between hinge axes 512 and 514.

Turning now to FIG. 41, another component support structure produced inaccordance with the present invention, generally indicated by thereference number 520, is illustrated which provides forthree-dimensional fine positioning. Structure 520 includes a cylindricalsupport tube 522, although any suitable form may be used, defining athrough-hole 524 for receiving an optical component such as, forexample, a lens or optical fiber. Support tube 522 is cantilevered froma base arrangement 526 and may flex for purposes of moving the opticalcomponent in the xy plane with stiff-spring constant K. A pair ofspring-attenuation feet 528 include manipulation/attachment tabs C and Dand a main tab 530. In each foot 528, a soft-spring element kinterconnects main tab 530 with its associated manipulation/attachmenttab, C or D. Main tab 530 of each foot is, in turn, fixedly attached tosupport tube 522. In the present example, this pair of feet isintegrally formed, but this is not a requirement. Coarse positioning isaccomplished by slidingly moving support structure 520 including tabs Aand B against a support surface (not shown) and then attaching thesetabs to the support surface. Fine positioning is carried out thereafterby manipulation of tabs C and D. These latter tabs are then attached toopposing sloped surfaces of base arrangement 526. Again, any attachmentshift at tabs C and D is attenuated in a highly advantageous way at thedistal end of support tube 522 by soft-spring constant k.

FIG. 42 illustrates another implementation of a support structure,produced in accordance with the present invention, and generallyindicated by the reference number 550. Structure 550 includes a base 552defining tabs A and B, and further defines a flexible springboard 554attached to the base. Springboard 554 supports a diagrammaticallyillustrated optical component 36 proximate to the distal end thereof. Amodified form of spring-attenuation foot 450 of FIG. 35 (or foot 302 ofFIG. 22) is provided, indicated by the reference number 555, which isconnected proximate to the distal end of springboard 554 and whichapplies a footprint to a surface 556 that is defined by base 552. Coarsepositioning in the indicated xz plane is accomplished by sliding theentire structure into a desired position against a mounting surface (notshown) and then attaching tabs A and B to that mounting surface. It isnoted that the movement and attachment modes, with their attendantadvantages, are readily employed, as is generally the case throughoutthis overall disclosure. To achieve at least y axis positioning,spring-attenuation foot 555 is used. Specifically, tab C is moved atleast along the y axis, and then attached to surface 556, therebyaccomplishing coarse positioning. Fine positioning then employs movementof tab D by which the position of component in the xy plane may beinfluenced. It is noted that in a slightly different implementation,springboard 554 may provide stiff-spring constant K whereby asoft-spring attenuation foot such as is shown, for example, in FIG. 41may be used, having a single manipulation/attachment tab. It should beappreciated that structure 550 accomplishes positioning in threedimensions.

Now directing attention to FIG. 43, it is to be understood that thesupport arrangements described herein may be combined in any number ofuseful configurations to achieve fine-adjustment and spring-attenuatedattachment shift correction in all dimensions. As an example, FIG. 43illustrates a combination support arrangement that is generallyindicated by the reference number 558 and which includesspring-attenuation foot 450 of FIG. 35 having its main tab 456supporting support structure 550 of FIG. 42. This configuration providesfor fine positioning along the x axis using foot 450 and along the yaxis using spring-attenuation foot 555 of structure 550, furtherproviding attachment shift attenuation, as well as fine positioning, inboth the x and y dimensions. As one alternative, the resulting structureneed not be produced as an assembly of two separate parts, but may beproduced integrally (not shown), for example, by machining.

Turning now to FIG. 44, it should be appreciated that the structures andmethod of the present invention may be employed for purposes ofimproving the performance of almost any mounting structure used in theprior art, and particularly those which exhibit attachment shift such asis seen, for example, in laser welding attachment. FIG. 44 embodies onesuch example using a four-legged support clip that is generallyindicated by the reference number 560. Clip 560 includes a centerportion 562 which supports, by way of example, an optical fiber 564using inverted U-shaped cross members. The fiber ferrule may be laserwelded to center portion 562 at weld points 566 and 568, among others.Generally, in the prior art, some level of precise positioning of thefiber is performed prior to initial welding of the ferrule to the clip.Finer adjustment is accomplished during and/or after the multiple-weldattachment of the optic to the clip. In terms of fine positioning, itwill be remembered from previous discussions that Jang, like other priorart implementations, at least some of which employ U-shaped clips,utilizes laser hammering whereby additional welds are made between theferrule and clip 560, thereby attempting to induce strains in strategiclocations to bend the mounting fixture back into a desired position.Still other prior art clip arrangements rely on post-weld bending, asdescribed above, particularly in attempting to compensate for attachmentshift.

Still referring to FIG. 44, the present example, in contrast to priorart techniques, serves to demonstrate the remarkable advantages whichaccompany the practice of the present invention. Specifically, the Jangclip is modified, as illustrated in FIG. 44, in a way which provides thebenefits of the present invention and which eliminates, based onApplicants' experience, the need for complex and potentially unreliablelaser hammering for the purpose of fine positioning and attachment shiftcompensation. Specifically, a four-hinge support arrangement 570 (see,for example, FIGS. 9 and 12) has been incorporated, in accordance withthe teachings of the present invention, including highly advantageousspring-attenuation feet 572 (see, for example, FIGS. 24 and 35). Ratherthan using a complex laser hammering procedure, fine positioning isaccomplished by direct engagement of feet 572 consistent with theteachings herein. As another example (not shown), the four-legged clipof Webjorn, described above, benefits from incorporating thespring-attenuated foot structure of the present invention at least inthe “front” pair of feet, close to the optical component. In essence,the foregoing examples serve to illustrate replacement of bending and/orlaser hammering with the more deterministic and generally more reliableapproach of the present invention. Accordingly, a wide range of supportstructures may benefit from the teachings herein.

Referring to FIG. 45, it should be appreciated the concepts andsub-structures directed to the use of spring-attenuation for thecombined objectives of fine positioning and attenuation of attachmentshift may be employed as features in virtually any structure thatexhibits some level of compliance in one or more dimensions. To that endand serving as a first example, FIG. 45 illustrates a supportarrangement that is generally indicated by the reference number 570 andis produced in accordance with the present invention. Supportarrangement 570 includes a base structure 572 that is made up of acenter, compliant block 574 that is arranged between a pair of pedestals576. Compliant block 574 may be formed from any suitable material suchas, for example, rubber, pedestals 576, likewise may be formed, forexample, from harder material such as a metal. At the same time,however, it is to be understood that the compliant block of FIG. 45, maybe representative of an elastic structure that is comprised ofunderlying simple and/or complex structures. The compliant block andpedestals are arranged on and attached to support surface 45 in order toaccomplish coarse positioning. An optical component is mounted in apassage 578 defined by compliant block 574. A pair of spring-attenuationfeet 580 are in communication with compliant block 574 and, in oneimplementation, may be formed integrally therewith, but this is not arequirement. Manipulation/attachment tabs 582 of the feet are disposedagainst upper surfaces of pedestals 576. With the optical componentmounted in compliant block 574, tabs 582 are manipulated in accordancewith the teachings herein and, thereafter, fixedly attached to pedestals576 in order to accomplish fine positioning while, at the same time,attenuating any attachment shift seen at the optical component whicharises upon attaching tabs 582 to the support pedestals. In thisexample, stiff-spring K is provided by compliant block 574, andsoft-spring k is provided by beams making up portions of feet 582,similar to teachings above. It is noted that the present example, akinto those of FIGS. 36, 39 and 41, utilizes a support structure whichitself intentionally serves as the stiff-spring. Other, previousexamples, at least to a good approximation, include structures havingseparate subcomponents, one of which primarily acts as a supporting,kinematic structure and another of which induces spring-attenuatedadjustment and which is employed primarily for purposes of attenuationof attachment shift.

As a second example, FIG. 46 illustrates a support arrangement that isgenerally indicated by the reference number 590 which resemblesstructure 570 of FIG. 45, but which includes a modified arrangement forinducing spring-attenuated forces against compliant block 574, as beingexemplary of one possible alternative to the use of accomplishingspring-attenuation without using flexural beam members. Specifically,arrangement 590 includes a pair of L-shaped feet 592 arranged formovement against the upper surfaces of pedestals 576 and subsequentattachment thereto in accordance with the teachings of the presentinvention. A compliant biasing member 594 is positioned between eachfoot 592 and compliant block 574. That is, member 594 may be attached atits opposing ends to compliant block 574 as well as one of L-shaped feet592. In view of the present example, it should be appreciated that anycompliant material or part, including an actual spring, may be employedin all or most of the structures described herein. As an example, FIG.47 illustrates a modified version of arrangement 590, indicated by thereference number 590′ using a pair of coil springs 596 as a replacementfor compliant biasing members 594.

In one general implementation of the teachings of the present invention,as described above, a structure and method for using aspring-attenuation mechanism is provided integral to the feet (or foot)of an optical mounting bracket to achieve both fine positioning anddecreased sensitivity to attachment shifts. In this regard,spring-attenuation advantageously provides for converting a given motionat one point into a corresponding smaller motion at another point. Thepresent invention exploits this advantage in a heretofore unrecognizedway at least to reduce the effect of horizontal (in plane) weld shiftson a final position of an optical component. A second benefit ofspring-attenuation resides in mitigation of the effect of stick-slip andother practical limitations experienced in adjustment resolution:whatever resolution is attained in manipulating manipulation/attachmenttabs is still further improved through attenuating action of thespring-attenuation foot mechanism of the present invention.

In this portion of the disclosure, specific design considerations andapproaches thereto are described that may be advantageous in achievingcontemplated attributes such as:

Reduction by a factor of 3 to 30 of in-plane weld shift, as measured atthe optical component, by using spring-attenuation.

High attenuation ratios attainable in a practical way within arelatively small footprint, as an advantage over conventional leverage.

Footprint minimization.

Flexible beams that may be sized and designed for a minimum of plasticdeformation. Beam configurations, described herein, are designed tominimize the extent of plastic deformation while maintaining arelatively small footprint.

If a bracket is designed for fine-adjustment in a plane orthogonal tothe optical axis, certain features in the foot may further reducesensitivity to attachment shifts in the direction of the optic axis by“absorbing” those shifts with flexible joints or members.

Bracket-foot configurations allowing for at least some fine-adjustmentin the z direction (generally, along the light path), as well asconfigurations allowing for angular adjustment.

Reduction of vertical attachment shift or tool-release spring-back bystrategic use of leverage: proper foot design and proper orientation inthe bracket still further reduces the effect of undesired verticalshifts, for example, vertical attachment shift of a foot. Certainfeatures can absorb vertical shift with flexible joints or members.

Thermal stability and long-term drift.

A conceptual understanding of “spring-attenuation”, as applied by thepresent invention, versus “spring leverage”, which is referred to in theliterature as well as mechanical levers in general.

It should be appreciated that spring-attenuation, as recognized herein,is not the only available mechanism for improving foot design tomitigate attachment shifts and to improve positioning resolution, evenif it ultimately becomes the most preferred and straightforward methodin view of this overall disclosure, as one aspect of the presentinvention. For example, levers, flexures, and other mechanisms mayalternatively be used to achieve various advantages. Moreover, theattachment or locked mode of the present invention serves as one examplewhich achieves highly advantageous attachment shift attenuation.Inasmuch as the use of spring-attenuation, as taught herein, is asweeping advantage standing in its own right, it should be appreciatedthat another fundamental recognition herein resides in the very notionof directly manipulating the feet of a support bracket for positioningan optical component. Accordingly, various foot-related mechanisms aredescribed in this disclosure in order to achieve even finer positioningresolution than that which is available using directly a directlymanipulated flat-footed bracket.

With regard to spring-attenuation versus spring-leverage, it should beappreciated that the spring-attenuation foot of the present inventionuses a series spring arrangement for fine positioning to provide areduced motion at some selected point relative to the motion of someremote point—the foot attenuates motion. While the prior art,particularly in the field of precision instrument design, refers to thisgeneral arrangement as “spring leverage,” it is important to understandthat this arrangement embodies important distinctions from what iscommonly referred to as a lever.

Specifically considering mechanical levers, any lever in anyconfiguration has a defining feature: mechanical levers transformbetween high-displacement low-force at one point and low-displacement,high-force at another—which makes their action reversible. Specifically,levers operate according to the most basic relationship(F×l)_(input)=(f×L)_(output). This force-displacement relationship iscommon to all simple machines that are based on actual “leverage”including inclined planes, threads, pulley blocks, and kinematicmechanisms. On the other hand, the spring-attenuation foot of thepresent invention transforms high-displacement input at one point tolow-displacement output at another point at nearly constant force.

Referring again to FIG. 35, unlike the action of a mechanical lever, theaction within the spring-attenuation foot of the present invention isnot reversible. That is, moving tab B results in attenuated movement ofmain tab 456. However, movement of main tab 456 does not produce anincreased displacement at tab B, thus moving inconsistent with themovement of a purely mechanical lever. This distinction is readilyapparent when compared to a structure which employs mechanical leverage.It is noted that the distinction applies to a soft-spring in series witha stiff-spring. Attaching any structure to main tab 456 which resistsits motion such as, for example, exerting force against a springboard,as in FIG. 42, or against a compliant block, as exemplified by block 574of FIG. 45, or a bracket, for example, including a flexible web member,as in FIGS. 13, 27, 29 and 30, will introduce another stiffness inparallel with the stiff-spring and will subsequently change the forcebalance. In one useful implementation, the stiff-spring of theattenuator is configured to be at least 10 times stiffer than anystructure attached in parallel with it; so, to a good approximation, theresulting force exerted by the structure on the stiff-spring element maybe ignored. In determining attenuation levels, the relationshipX/x=(K+k)/k applies where k is the soft-spring value and K is thestiff-spring value. X represents an actual, applied movement magnitudeand x represents the attenuated movement magnitude. For values of K/kgreater than 10, this relationship may be approximated as X/x=K/k.According to this latter definition, attenuation always has a value thatis greater than one. As a note, when the soft and stiff-springs are ofequal stiffness, the attenuation is equal to two.

It is considered that the design of beam elements to provide strengthand stiffness suitable for use herein is within the capability of onehaving ordinary skill in the art in view of this overall disclosure.Accordingly, the scope of this discussion is limited to specialconsiderations in the context of the present invention for minimizingresidual stress and shrinking the overall footprint ofspring-attenuators.

Initially, it should be recalled that the kinematic structure (forexample, three and four-hinge class structures described above) attachedto the spring-attenuation foot itself influences the correlation betweenspring-attenuated output (or overall foot position changes) and motionat the optical component; this correlation is not necessarily a 1:1correspondence.

A spring-attenuator mechanism may be approximated by three parameters,as follows:

Attenuation: A ratio of input displacement of the soft-spring to outputdisplacement of the structure. In the present application, it is anobjective to attenuate, or reduce, the attachment shift.

Range-of-motion: A maximum extent of optic motion that can be achievedby moving the fine-adjust feature or tab. Range-of-motion of the opticalcomponent is equal to the total travel of the fine-adjust (soft-spring)divided by the attenuation. Maximum fine-adjust travel is limited byplastic deformation in the soft-spring, and is therefore a function ofboth material properties and geometry. (Note that for purposes herein,the range of motion at optical component is smaller than the travel ofthe fine-adjust.)

Maximum allowable force: The force required to push the fine-adjust toits maximum extent.

For a given overall size, the designer selects a balance between rangeof motion and attenuation: longer range of motion implies lowerattenuation, since the maximum fine-adjust deflection is essentiallyfixed, being limited by size and geometry. Clearly, the bare minimumrange of motion for the structures herein is driven by the nominalaggregate uncertainty of positioning and attachment shift during thefirst stage of adjustment and attachment—after initial “coarsepositioning” attachment there is some net error in the position of theoptical component which must fall within the range of motion, at theoptical component, allowed by the spring-attenuator and the kinematicstructure. In practice, the range of motion often must be larger yet toaccount for manufacturing tolerances in the height of the optic axisrelative to the mounting surface. For the most part, the structuresdisclosed herein exhibit 4 to 12 times attenuation and a 10 to 25 μmoptic range of motion, using brackets made, for example, with stainlesssteel.

Another important design consideration has to do with force: thespring-attenuator must be capable of producing the force needed todeform or move the kinematic structure. The minimum input force appliedto the spring-attenuator during adjustment is that required to deformthe structure, therefore it is desirable to minimize the amount of forcerequired to control the structure. This, in turn, assures that anyapplied force provides the desired range of motion for a minimum stress.As one example, in the three-hinge class of structure (see, for example,FIG. 22), this is accomplished by thinning the hinge areas. For elasticand four-hinge types of structures (FIGS. 27 and 28, respectively),somewhat stiffer hinges are required to provide a minimum stiffness toresist shock and vibration, as described previously, which requires theattenuating feet to exert correspondingly more force. Maximum force islimited by the onset of plastic deformation in the soft-spring.

In the spring-attenuation foot, as exemplified at least by FIGS. 24, 35and 37, the spring elements consist of beams, which to the first ordercan be modeled using handbook equations for beam stiffness. A “beam” isusually understood to mean a structural element that is loaded primarilyin bending, although the actual stress and deformation state of a realbeam will result from all loads: bending plus compression, torsion, andapplied moments. One important aspect of beams for spring-attenuatordesign herein resides in allowing large differences in stiffness withminor variations in geometry—this property of beams allows for producingspring-attenuators within a remarkably small footprint. It is noted thatthe scale length for these systems is fundamentally driven by the size(and therefore mass) of the optical component; for example, apositioning and attachment bracket ten times smaller than the lens wouldprobably not be rigid enough to hold the lens for typical shock andvibration specifications. The stiffness of any beam without appliedmoments depends on the third power of the ratio of depth to length,where depth and length dimensions are measured in the plane ofbending—the plane of the foot. For example, a beam 2.1 times deeper thananother of the same length will be about ten times stiffer in bending,providing eleven times motion attenuation. This is strictly true for“flexural” beams—those at least about ten times longer than they arewide—and becomes less accurate as this aspect ratio decreases. For loweraspect ratios, the designer should consider the effect of shear andlocal changes in beam cross-section, which is most easily accomplishedwith Finite-Element Analysis (hereinafter FEA).

Continuing to describe spring-attenuator design considerations, thesoft-spring will usually experience higher peak stress than thestiff-spring. One reasonable design goal for the soft-spring is tominimize its stiffness while keeping peak stress within an acceptablelimit—about 80% of yield for designs herein. This is most effectivelyachieved by making the beams longer, but this increases the footprint[Stiffness/max stress is proportional to (1/length²) multiplied by(Modulus/yield stress)]. Another option is seen in choosing a materialwith a high ratio of elastic modulus to yield stress such as berylliumcopper, titanium or hardened steel. Of course, any suitable materialthat is currently available or yet to be developed may be utilized basedon various considerations. For example, titanium and beryllium copperare more expensive, more difficult to work with, and less safe to handlethan steel, while full-hard steel will not allow plastic deformation forforming the structure or bending the hinges. Quarter-hard stainlesssteel presently appears to provide a favorable compromise between theneed for plastic deformation in the structure and the need for a highratio of elastic modulus to yield stress in the soft-spring. The type ofstructure described with reference to FIGS. 36 and 37 allows thesoft-spring and stiff-spring elements to be formed from unlike, but mostappropriate materials such as, for example, beryllium copper for thesoft-spring and annealed low-carbon steel for the stiff-springstructure.

Regardless of the material choice and available footprint, theparticular geometry of the soft-spring will have the most significanteffect on its stress distribution. In one approach, the material may beused as “efficiently” as possible—to strain the largest amount ofmaterial as nearly uniform as possible. This consideration suggestssoft-spring beams that are curved with a radius of the same order ofmagnitude as the beam length, compound fillets at the roots (i.e., endsof the beam), and an overall taper from the roots, where bending stressis highest, to center, where the lengthwise stress is highest. Beamsemploying various combinations of these features are seen throughout thefigures, but fabrication techniques can limit the extent to which all ofthese design features may be employed in any particular volume-producedattenuator design. None of the designs shown are particularly divergentfrom what can be accomplished through a variety of reasonably low-costmanufacturing techniques. FEA is indispensable for designing beams withsuch complex features and only a few well-chosen design iterations areneeded to produce an acceptable design for a particular application.

One highly advantageous structure for spring-attenuation, shown in FIG.48 and generally indicated by the reference number 600, includes twosymmetric pairs of planar beams with different depths with the soft beam(k) pair indicated by the reference number 602 and the stiff beam (K)pair indicated by the reference number 604. Hinging positions (H) areindicated by the reference number 606. Manipulation/attachment positionsor tabs are indicated as A and B, with the latter comprising the finepositioning adjustment tab. It is noted that foot 600 is a modified formof foot 302 of FIG. 24, as will be described. With tab A attached to asupport surface (not shown), foot 600 advantageously provides a nearlypure translation movement to hinges H without significant twisting outof the plane of the foot. The positions of hinges 606 are made nearlyinsensitive to undesired foot rotation during attachment or manipulationby arranging the hinge axis (common to both hinges), stiff-spring K, andthe initial attachment point A, all at least approximately collinear.Spring/beam regions are preferably slightly thinner (not visible in thisview) than remaining portions of the foot, such that the beam members donot themselves slidingly contact the support surface. This arrangementnot only provides a smoother motion during fine-adjustment, but furtherserves to prevent the beam/spring elements from sticking, for example,on a piece of dirt or surface irregularity during adjustment, only torelease later and misalign the optic. While this feature is desirable,it may be difficult to produce with certain fabrication methods and may,therefore be omitted without substantially limiting any of thefunctionality of foot 600 with its attendant advantages. In this regard,Applicants have empirically and routinely observed tenth-micronresolution when sliding stainless steel metal feet over a stainlesssteel supporting surface. It is noted that incorporation of this reliefin the beam elements will, however, allow the stiff beam to deflectvertically as a reaction to the forces and moments imposed by deformingthe structure. Therefore, the stiff beams should be formed sufficientlyshort and wide so as to avoid bending contact with the supportsurface—such a situation could potentially create an undesirablestick-slip motion of the optical component during fine-adjust or producea shift after the device manufacture is complete.

Still referring to FIG. 48, one way in which foot 600 differs frompreviously described foot 302 of FIG. 24 resides in the configuration ofmanipulation/attachment positions A and B. That is, rather than thecircular configuration shown in FIG. 24, these positions are shown inthe present figure having a generally square configuration with roundedcorners. This may be an advantageous configuration for use inspring-attenuated feet. Surprisingly, however, manipulation tool 90(see, for example FIG. 3) is used having circular manipulation shoulder98. This arrangement, using a round tool in a square hole, is thought toadvantageously minimize “cross-coupling” during foot manipulation. Asthe tool is moved in a direction perpendicularly with respect to onesidewall of the square manipulation position, it engages/disengages onlythat sidewall. In contrast, where the recessed circular sidewall of acircular foot manipulation position is larger in diameter than thediameter of a circular manipulation shoulder that is used to engage it,the tool may engage the circular sidewall of the manipulation positionat a point not exactly collinear with the motion of the tool. Dependingon the coefficient of friction and the relative sizes of the twocircular diameters, this could lead to a slight component of motion thatis normal to the direction of travel of the tool (a cross-coupledmotion) and make the optimization a bit more complicated.

The square pocket manipulation configuration of FIG. 48 serves in a waywhich is thought to prevent this by ensuring that, if the tool movesapproximately perpendicular to a sidewall, the foot will move in thetool direction. At the same time, it should be appreciated that for agiven tool outer diameter, the square pocket is necessarily larger inarea than a circular pocket. During attachment by welding, this largerdistance between weld pool and the thicker portion of the foot may allowthe thinner portion in the weld region to deflect more upon welding soas to produce slightly more attachment shift. For this reason, round,minimum-sized manipulation positions may be used for feet withoutspring-attenuation, and the square manipulation positions may be usedfor structures with spring-attenuated feet. Alternatively, a foot mayinclude a combination of circular and square manipulation positions. Forexample, Position A in the present illustration may have a circularconfiguration (not shown) while position B may have a squareconfiguration. In sum, it should be appreciated that attachment shift isgenerally not particularly critical when using spring-attenuated feetsuch that a balance may be struck between attachment shift and precisepositioning.

While foot 600 of FIG. 48 produces sufficient attenuation for use inimmediate applications and provides a quantum improvement over manyaspects of the state-of-the-art, the present invention contemplatesvarious other applications, for example, that may require still fineradjustment or which may be directed to reducing larger attachmentshifts. In addition to increasing beam length, many other configurationswhich rely on the teachings herein are possible for producingarbitrarily high attenuation while making efficient use of space, aswill be seen.

Referring to FIG. 48 a, foot 600 is illustrated in a relaxed state, asoutlined by dashed lines and in an adjusted or deformed footprint state,as outlined by solid lines, after having moved manipulation position Bin an x direction, as indicated by an arrow. In this regard, it shouldbe noticed that movement of manipulation position B by a distance M inthe x direction, caused by direct manipulation, is significantly greaterthan the resultant movement ΔM of hinging positions 606 in the xdirection, thereby illustrating the highly advantageous springattenuation action of foot 600 which is consistent with such actionprovided by all of the spring attenuation feet described in the contextof this overall disclosure.

Turning to FIG. 49, an alternative spring-attenuation foot produced inaccordance with the present invention is generally indicated by thereference number 620. Legs 622 (partially shown) form a portion of anoverall support structure and are attached to hinging positions 604.This foot differs from foot 600 in its use of a soft-spring 623 with aflattened coil or “serpentine” shape, thereby providing a very lowstiffness within a small footprint and maximum stress. Again, thedesigner should consider out-of-plane buckling for spring elements ofthis type, especially if the distance between the ends of the spring islong relative to the material length of the spring.

Referring to FIG. 50, another alternative spring-attenuation foot,produced in accordance with the present invention, is illustratedgenerally indicated by the reference number 640. Foot 640 includes outof plane, arched springs 642 serving as soft-spring elements and whichare hinged to tabs A and B for purposes of increasing attenuation whileminimizing footprint. It is noted that these arched springs may besomewhat challenging to form with repeatability, and are formed bestwith annealed metal. In this connection, however, it is thought thatacceptable tolerances are quite readily achievable in view of increasedattenuation levels.

Referring to FIG. 51, a slightly modified form of three-hinge bracket300 is illustrated, indicated by the reference number 300′, again forpurposes of describing its functionality responsive to attachment shiftsand, particularly, weld shifts. Tabs A and B are indicated, consistentwith the FIG. 48 described above, while optical component 36 includes anoptic axis 648. Applicants have observed experimentally that weld shiftsoccur in any direction, which is seemingly random. Although the presentapplication has, thus far, primarily discussed how the structuresdescribed herein perform in a direction 650 indicated by arrows, thatis, for movement of either foot towards and away from the other foot, itshould be noted that the support arrangements of the present inventionare specifically designed to provide spring-attenuation of a weld shiftoccurring in any direction. To that end, the manner in which the supportstructures of the present invention attenuate weld shift which occurs atfine-adjustment positions (tab B), for example, in directions 652,indicated by double-headed arrows, that are parallel to optic axis 648(still in the plane of support surface 45), and a “vertical” shift(perpendicular to both support surface 45 and optic axis 648) will bedescribed immediately hereinafter.

Still referring to FIG. 51, for a weld shift at tabs B in the directionparallel to optic axis 648 (along direction 652), arc-shapedsoft-springs k deform in much the same fashion as for a shift indirection 650. Responsive thereto, stiff beams K provide a rotationalstiffness at a point 652 (only one of which is indicated), which is ofthe same order as its translational stiffness. For most configurations,a soft-spring with uniform stiffness in the plane of the support surfaceis a natural result of designing the beam for minimum stress and maximumdeflection, as described previously. It is important that soft beam k besufficiently thick in the region near the attachment point to stiff beamK so to prevent unexpected deformation during manipulation.

By simple modification of stiff beam K, the structure may be designedexplicitly to include fine-adjustment in the direction along optic axis648, in addition to attenuating shift in this direction. One example isshown in FIG. 51, in which a small notch 654 has been cut from the endof stiff beam K. This reduces the rotational stiffness of the stiff beamabout point 652, while retaining most of the translational stiffness. Asdescribed above, a motion along optic axis 648, or a rotation of thefoot in the support plane may be advantageously used to produce atwisting or degree of “pitch” to the optic when connected to anappropriate structure.

Continuing to refer to FIG. 51, for a weld shift in the verticaldirection (normal to feet 302), soft-spring k will be slightly stifferthan for in-plane shifts and stiff beam K will usually be less stiff(loaded in nearly pure torsion) than for in-plane shifts. However, thetooling and attachment scheme of the present invention limits verticalshifts at the fine-adjust point due to welding or tool release, aspreviously described. In practicing the present invention, Applicantshave observed vertical shifts routinely less than 0.5 μm. This motion isreduced not only by the spring-attenuation of the foot structure, butalso by mechanical leverage. It is observed that a vertical motion attab B produces a motion at hinges 314 in an opposite direction accordingto lengths projected parallel to direction 650 (shown adjacent to one ofthe feet) in a ratio of a first projected length L1, between hinge 314and an effective end of the stiff beam, to a second projected length L2,between tab B and the effective end of the stiff beam. That is tab B (atthe center of the attachment shift) and hinge axis 50 (or 52) form theends of levers, each having an effective fulcrum position provided bythe twisting of stiff beam K. As previously discussed, the attachmentshift responsive motion of hinging position 314 is further reduced atthe optic by structural attenuation.

Referring to FIG. 52, a spring-attenuation foot structure, produced inaccordance with the present invention and generally indicated by thereference number 660, is illustrated which uses separate spring elementsto attenuate motion in respective directions. Specifically, a beam 662allows fine-adjust attachment point B to shift parallel to the opticaxis, in a direction 664, without causing a significant motion of thestructure attached at hinging positions H (also indicated by referencenumber 314); consequently, however, beam 662 does not allow forsignificant correction of attachment shifts in direction 664. It shouldbe appreciated that this foot structure is a variation relating tofundamental recognitions and teachings herein. In one exemplaryimplementation, foot 660 may be useful for fitting into certain devicesthat constrain the shape of the spring-attenuator footprint.

Referring collectively to FIGS. 53-54, as will be described in furtherdetail, configurations are demonstrated in which the spring elements donot reside separately in the foot or the end of the leg of thestructure, but are integral to the structure itself. These structuresattenuate weld shift in the plane perpendicular to the optic axis,similar to the structures previously described; but, they are relativelystiff in the direction of the optic axis and do not providespring-attenuation in this dimension. In this regard, lenses, like otheroptical components are least sensitive to motion along their axis, sothese structures remain very useful for lens mounting, among otherapplications.

Turning specifically to FIG. 53, a support structure, produced inaccordance with the present invention, is generally indicated by thereference number 680. This structure may be coarsely positioned (forexample with a “pick and place” robot) on a support surface (not shown)and attached at tabs 682. A comparison of structure 680 with previouslydescribed structure 500 of FIG. 40 may be made by the reader in order togain a sufficiently complete understanding of its attributes. Slidingtabs 684 against support pedestals 686 provides fine-adjustment of anoptic holder cradle 688 within a plane that is at least generallyperpendicular to an optic axis 690. An optical component (not shown) maybe supported and attached in cradle 688 in any suitable manner so as todefine optic axis 690. During the initial coarse positioning, novertical adjustment is available; accordingly, fine positioning providesthe entire required range-of-motion for vertical adjust. A typicalvertical coarse positioning accuracy is ±0.0005 inch. With aspring-attenuation of 10×, the required range of motion of tab 684 isthen 0.005 inch for vertical adjust, and an additional 0.005 inch forhorizontal adjustment. Moving tab 684 by 0.010 inch provides anapproximately 0.0025 inch radius range of motion to the optic with 10×attenuation of the attachment shift.

Still referring to FIG. 53, to accommodate such a relatively large rangeof motion during fine positioning, hinges 692, 694 and 696 functionindividually as structural kinematic hinges, and collectively as aportion of the stiff-spring. The remainder of the stiff-spring stiffnessis generated by hinges 698. All stiff spring hinges are allowed todeform plastically, but still provide an effective stiffness that is atleast ten times greater than the stiffness of U-shapedspring-attenuation elements 700. The concept of allowing thestiff-spring element to deform plastically may be applied to anystructure herein to increase the available range-of-motion. The numberof adjustment cycles is determined by factors including material strainhardening such that special design consideration should be given tomaterial choice and analysis of residual stress.

FIG. 54 illustrates a support structure 720 which still more closelyresembles structure 500 of FIG. 40, including support cradle 688 forreceiving the optical component.

Turning to FIG. 55, another implementation of a foot in accordance withthe present invention is generally indicated by the reference number740. Foot 740 includes attachment tabs A and B, consistent with previousdescriptions as well as a hinging axis H. Like previous implementations,the foot is first attached at a tab A, then re-adjusted and secondlyattached at a point B in a way which produces advantages consistent withthose described above. In this form of structure, a linkage causesdeformation of the foot and a motion at H that is less than the motionof tab B. Specifically, this particular example uses a kinematic linkagecomposed of flexural hinges 742 and thicker struts 744. It is notedthat, as struts 744 a become more nearly orthogonal to struts 744 b, theamount of attenuation increases and the available range of fine-adjustmotion decreases. It should be appreciated that there are manyconfigurations for achieving this mode of reduction. One potentialadvantage of this embodiment resides in the fact that the finalstiffness provided by the foot to point H may be higher than that in asystem based on elongated spring-attenuation members. High stiffness,however, is not required for immediate purposes, but could beadvantageous for a structure required to produce larger forces in orderto position the optic. Moreover, both approaches to foot design usedirect manipulation, spring-attenuation feet in a manner that isconsistent with the overall teachings of the present invention.

Referring again to FIGS. 4 and 5, attention is directed to one aspect ofthe attachment mode wherein friction is employed to resist attachmentshifts, for example, during attachment by welding. In this regard, itshould be appreciated that the bias force 100, used to increasefrictional resistance to weld shifts, may be capable, in some instances,of generating changes in the shape of the mounting surface immediatelybeneath the foot which, in turn, may result in changed optical couplingwhen the biasing force is removed. Any such effect is readily minimizedor essentially eliminated, however, by supporting the structure directlyunder the positions where force is applied. It should be recognizedthat, for a given optical module, there are numerous configurations thatmay be employed; the magnitude of the subject effect will, of course,vary depending on the structure, as will the various options foraddressing it. Those skilled in the art will recognize that one verystraightforward approach is to support the module directly underneaththe spots where a biasing force is applied, and to avoid exerting forceelsewhere on the module.

In very limited cases, a vertical bias force of several pounds, in orderto implement the attachment mode, may be unacceptable. In thesesituations several options remain:

1. Lower biasing forces may be employed so long as tolerances andresulting alignment precision remain acceptable.

2. Again, lower biasing forces may be employed, recognizing thatadjustment precision is reduced. Responsively, spring-attenuation isdesigned in to provide correspondingly larger attenuation so as to“absorb” resulting, larger attachment shifts. This approach maypotentially require a larger footprint and/or a reduced fine-adjustmentrange.

3. Use rigid motion stages and manipulators, as opposed to frictionalforces, to resist attachment shift.

4. Use some balance struck between two or more of these items 1-3.

With regard to item 3, the use of “hard” tooling in these limitedcircumstances, it should be appreciated that the manipulationconfigurations described above are either useable as-is or readilyadaptable. For example, the sharp tip manipulation configuration shownin FIGS. 18 and 19 may be used. In embodiments using a manipulationrecess in the foot (see, for example, FIGS. 14 and 15, the manipulationtool and cooperating recess may employ, for example, a conicalconfiguration so as to eliminate play between the foot and manipulationtool to rigidly hold the foot in place during attachment. In thisregard, Applicants are unaware of any prior art approach that uses suchclamping or gripping of a foot arrangement in order to resist attachmentshift. This alternative approach taken by the present invention isconsidered to be highly advantageous in and by itself.

Once again considering thermal design and long-term stability, thepresent invention incorporates design features intended to prevent driftfor the rated lifetime of the device, typically twenty years. Mechanismscontributing to drift include: differential expansion during devicetemperature cycles, external shock and vibration, and creep.

Optoelectronic devices must operate over a temperature range that variesby 50 to 100° C. Considering that typical values of Coefficient ofThermal Expansion (CTE), change-in-length per length per unit change intemperature, for metals is approximately 10 to 20×10⁻⁶/° C. and thepositioning structures herein are dimensionally on the order of 1 to 8mm, a structure designed without regard for temperature performancecould move the optic by approximately 5 to 20 microns over a 100° C.temperature change—potentially causing degradation of deviceperformance. Accordingly, the support structures of the presentinvention are designed with consideration for the material CTE andstructural kinematics, such that the optic is provided with an effectiveCTE that is appropriate for interfacing with other components in aparticular application. For example, if the lens mounting structure, thesupporting surface, and the lens holding ring are all made of materialwith the same CTE, all dimensions change by the same proportion, suchthat the lens moves as if it is attached to a solid block of a materialwith that CTE. Any differences in CTE between components require thedesigner to also consider the kinematics of the structure.

The spring-attenuator feet shown, for example in FIG. 48, are largelyathermal, even when the supporting surface has a different CTE, providedthat the attachment point on tab A and the hinge points H are at leastapproximately collinear. Furthermore, any motion caused by differencesin CTE between the spring-attenuator foot and the supporting surface issubject to spring-attenuation and, hence, is divided by the attenuationvalue.

As a structure deforms slightly with temperature changes, regions thathave deformed plastically will change responsive to changing internalstresses. The slight motion of these regions as “yield boundaries” couldcause a redistribution of internal stress and may be a mechanism forlong-term drift of the structure. Accordingly, the spring-attenuators ofthe present invention may be fabricated from ¼-hard steel and aredesigned to induce a maximum stress that does not exceed yield.

Creep should not contribute substantially to drift. Although the stressin some of the spring-attenuators of the present invention may be within50 to 80 percent of yield in some areas, the temperature of thestructure normally remains below 100° C., which is less than 10% of thepreferred materials' melting temperatures.

The use of laser welding has been described in detail above for purposesof forming attachments in the context of the present invention, however,it is to be understood that other attachment techniques may be utilizedincluding, but not limited to other types of welding, soldering, oradhesive-based forms. It should also be understood that the benefitsderived from the structures and method described herein extend not justto attachment by laser welding, but to any suitable method ofattachment.

Significant benefits associated with the practice of the presentinvention include:

Reduced or essentially eliminated spring-back due to disengagement oftool or clamp, by restricting engagement of the mounting bracket to thevery hardest segment—mainly the top of the foot or feet. Assuming themost basic precautions against warping of the feet, mentioned below,this benefit extends to methods of attachment considered to be withinthe scope of basic structures and methods described herein.

Frictional force between the foot and the mounting surface providesresistance to attachment shift, regardless of the method of attachment(welding, adhesive, etc.), as long as basic precautions are followed, asdescribed. In this regard, it is clearly helpful to insure that thebottom of the foot and the top of the mounting surface are in intimatecontact, with some vertical biasing, over at least a fraction of thetotal footprint.

The sheer simplicity of the attachment method, i.e., a flat plate beingbonded to a flat surface, is conducive to high integrity bonds withminimum shift for any suitable bonding method. Other structuresthroughout the prior art typically use at least several joints with lesssymmetry and lower “ease of use.” The fact that the present inventionadjusts position by pushing the feet around, in the first instance,enables a remarkably effective use of flat plates as feet.

The kinematic structures of the present invention perform their basicfunctions irrespective of the attachment method. Main functions of thesestructures include, for example, providing support to the optic,allowing for adjustment of the optic along a predetermined pathdetermined by the motion of the feet, and attenuating foot shifts at theoptic as desired by application of mechanical advantage in thekinematics.

In cases where attachment shift requirements are not fully satisfiedusing foot manipulation and frictional shift resistance,spring-attenuators may be designed into the feet so as to still furtherreduce attachment shift, regardless of the chosen bonding technique.

Briefly considering the motivations which continue to drive the priorart, a traditional reliance on laser welding is thought to be seenlargely for two reasons: first, the field of heating is modest whencompared to most brazing or soldering, which helps reduce shift andwarping. Laser welding is itself a form of spot-welding, to the extentthat the field of heating is limited to the vicinity of the weld spotmuch in the same way as in properly managed resistance spot-welding.Certainly in photonic device manufacturing it is beneficial to minimizethe field of heating—one does not generally want to “cook” the entiremodule in order to make an attachment. Second, perhaps more importantly,laser welding is a non-contact method. In this regard, it is submittedthat most configurations in the prior art would behave very poorly ifthe attachment system came into contact with the assembly duringpositioning and attachment. For example, in all of the prior art methodsof which Applicants are aware, it would be extremely difficult toutilize resistance spot-welding without suffering large shifts, sincetypical spot-welding electrodes apply several pounds of force.

By contrast, the approach of the present invention lends itself rathernicely to spot-welding. Specifically, the present invention already mayuse an electrode-like structure for positioning; and already mayintroduce several pounds of force at the tool in order to achieve finepositioning and minimal shift.

Based on state-of-the-art resistance spot-welding, so called “parallelgap” resistance spot-welding appears as an attractive and highlyadvantageous option in the context of the present invention. Theparallel gap technique is typically preferred for resistancespot-welding a thin metal plate (2-10 mils) to a thicker metal plate(>50 mils); the use of parallel probes provides a mechanism to minimizeheating of the thick mounting plate, since the current path follows acurved path limited to the neighborhood of the weld, as is known in theart.

Referring to FIG. 56, one configuration of a system using parallel gapresistance spot-welding, in accordance with the present invention, isgenerally indicated by the reference number 760. System 760 includes afoot 762 having a lowermost support surface (not visible) that slidinglyengages a support surface 764 of a support structure 766 which is onlypartially shown. Foot 762 includes a pair of indexing recesses 768 andis hingedly attached to an overall support structure which is onlypartially illustrated. Indexing recesses 768 may comprise slight divotsin the upper surface of foot 762 which may be formed, for example, byetching. Peripheral sidewalls of the recesses may be as small as, forexample, 1 mil. A manipulation/attachment tool 770 includes a pair ofmanipulation and weld electrodes 772, shown hovering immediately aboverecesses 768 for purposes of illustrative clarity and about to engagethe recesses. One of the benefits of system 760 resides in thecapability to simultaneously use the weld electrodes as a manipulationtool in the manner illustrated. That is, electrodes 772 may be used topush against the peripheral sidewall of recesses 768 with the lowermostsurface of foot 762 in sliding engagement with surface 764 in a mannerthat is similar to that described with regard to region 84 of FIG. 3.Moreover, the aforedescribed movement and attachment or locked modes,along with their attendant advantages, are equally applicable withregard to this implementation. It is noted that a circular configurationof electrodes 772 and recesses 768 is not required and that any suitableshape, such, as for example a square pocket or recess may be used. Withregard to details concerning the attachment mode, when the spot-weld isactually accomplished, it is noted that pressure may be applied toindexing recesses 768 in a highly advantageous manner with respect tolimiting attachment shift since downward biasing force applied byelectrodes 772 is in the immediate weld region, as will be describedimmediately hereinafter.

With regard to reduction of attachment shift, it is recognized hereinthat spot-welding force requirements, typically several pounds such asemployed in the system of FIG. 56, and similar implementations, areconsistent with the desired force needed to manage weld shift byutilizing friction, as described in the teachings above which considerlaser welding using the highly advantageous feet of the presentinvention. The fact that the welding electrode and the manipulator areone and the same is even further advantageous in eliminating the need toclear the laser beam, as in laser spot-welding. In the context of laserwelding, it will be recalled that to avoid spring-back from toolliftoff, the weld spot was placed as close as physically possible to themanipulator tip. In the case of spot-welding this occurs naturally,insuring that the tool liftoff occurs very close to the weld nugget,hence minimizing spring back due to micron or sub-micron warping of theplate in the vicinity of the weld.

Turning to FIG. 57, an alternative configuration of system 760 isillustrated wherein a foot 762′ includes a void 780 in the form of aslot or gap that is introduced between recesses 768 to reduce so called“shunt” heating of the foot—with the intention of eliminating certaincurrent paths that produce excess heating.

Another useful form of attachment is known as “resistance spot brazing.”In this process, the parts to be joined (i.e., lowermost surface of afoot as well as the support surface engaged therewith) are coated, atleast at the joining surfaces, with brazing materials having a lowermelting temperature than the parts to be joined. In the context of thepresent invention, this method can be used to reduce the field ofheating, which may in turn reduce weld shifts, reduce warping, and allowfurther control over the extent of the weld nugget, since the nuggetcannot penetrate deeper than the coating. Still further control of theweld nugget is provided in a specific implementation to be describedimmediately hereinafter.

FIG. 58 is an elevational view, in cross-section, taken through amodified foot 762″, a modified support structure 766′ and tool 772 whichillustrates an alternative configuration of system 760 for purposes ofattachment in the practice of the present invention using resistancespot brazing. More specifically, this configuration resistance brazesfoot 762″ and support structure 766′ to one another. To that end, foot762″ includes a first inset 790 that is filled with brazing materialwhile support 766′ includes a second inset 792 that is also filled withbrazing material. Heating is induced using electrodes 772 in a mannerthat is known in the art. With regard to this alternative configuration,it is suggested that physical asymmetries in weld nuggets may often be afactor in producing weld shifts—misshapen and oblong weld nuggetsexhibit less symmetry and are more likely to pull in a preferreddirection—by introducing a well-defined finite braze area, and applyingjust enough heat to insure that insets 790 and 792 both melt entirely,the production of a well-defined symmetric weld nugget is contemplatedwhich, upon cooling, may produce less shift.

Having considered various attachment techniques using welding, adhesiveattachment techniques will now be addressed for use in the practice ofthe present invention. Initially, if it is assumed that adhesive isstrategically introduced so that some fraction of the footprint of thefoot remains in contact with the mounting surface, the position of thefoot may be adjusted prior to curing—in this method, the curing step isanalogous to spot-welding, as taught above.

Continuing to discuss adhesive attachment, adhesives generally requireat least a minimum bond thickness. Clearly, in sub-micron precisionmounting, adhesive bonding flat plates to a flat mounting surface may beproblematic if no measures are taken to achieve sub-micron level controlover the final adhesive thickness. The configurations shown in FIGS.59-63 representatively address this issue. Generally, inset adhesiveareas insure a specific glue thickness while peripheralsurface-to-surface contact sets the foot height before and afterbonding. The manipulation tool is intentionally placed over an area withsurface-to-surface contact in order to minimize spring back.

Referring to FIG. 59, an adhesive attachment system is illustrated,produced in accordance with the present invention and generallyindicated by the reference number 800. System 800 includes a foot 802defining one recess 768, however, a pair of recesses may be providedwhere the capability to twist the foot during manipulation is desired.Again, foot 802 is hingedly attached to an overall support structurewhich is only partially shown. Manipulation of foot 802 is performed byengaging recess 768 using a manipulation tool 804 having an engagementend 806 and moving the foot against support surface 45.

Turning to FIG. 60 in conjunction with FIG. 59, the former provides aperspective, bottom view of foot 802 wherein it is seen that the footincludes a pair of parallel adhesive insets 808 arranged spaced equallyoffset from manipulation recess 768. With regard to the latter, itshould be appreciated that a manipulation recess is not a requirement,as an exemplary alternative, foot 802 may be configured in a manner thatis consistent with that shown in FIGS. 18 and 19, using a sharpmanipulation point which penetrates the surface of the foot to a limitedextent for accomplishing manipulation of the foot. Associateddescriptions of FIGS. 18 and 19 provide specific details with regard toimplementation of such an arrangement. In all of the adhesive-basedimplementations described, care should be taken to avoid adhesiveworking out of the adhesive insets during the adjustment phase, whilethe foot is manipulated against the support surface. One approachresides in injecting the adhesive through holes (not shown), after finepositioning is achieved. As a further enhancement, a pattern of holes(not shown) in the top of the foot extending to the position of theadhesive may be useful for admitting UV rays in the case where a UV cureepoxy is used. With regard to adhesives that are suitable for useherein, any suitable adhesive currently available or yet to be developedmay be used. Presently available options include, as examples, thermallycured epoxy or UV cure epoxy.

It should be appreciated that there are other ways to insure a setheight of the foot against the support surface when potentiallyinfluenced by adhesive. For example, if no adhesive reservoirs or insetsare provided, another approach may use a powder-loaded or bead-loadedadhesive. Applicants have found that glass powder loaded UV cureadhesives work very well to maintain a set gap when two surfaces arepressed together. It appears from empirical data that the glass powderacts to maintain a gap size roughly equal to the average size of theglass bits—the glass powder granules hold the two surfaces apart to setand maintain a natural spacing before and after curing.

FIGS. 61 and 62 illustrate system 800 including a modified foot 802′.Specifically, as seen in FIG. 62, the foot includes a circular adhesiveinset 810 which surrounds recess 768 in an equidistant manner in thesense of a plan view. FIG. 63 illustrates still another arrangement ofadhesive insets indicated by the reference number 812 wherein theadhesive insets comprise wedge shaped cavities arranged so as tosurround manipulation recess 768 in the sense of a plan view. It is tobe understood that adhesive recesses may include an essentiallyunlimited number of configurations, all of which are considered to fallwithin the scope of the present invention, and that the specificconfigurations shown herein are not intended as being limiting.

Soldering is still another attachment approach which may be used in thepractice of the present invention for purposes of foot attachment. Onemanner in which this approach may be implemented includes heating theentire area around a support bracket wherein the support bracketincludes a pair of feet, which in many cases would be synonymous withheating the entire base-plate on which the mounting surface is located.Adjustment of the position of the feet, and hence the optic, is thenaccomplished before cooling the system so as to permit the solder toharden. If the bracket feet and the mounting surface are composed ofnon-solderable metal, appropriate surfaces may be plated withnickel-gold layers, or some other solder-compatible metals known tothose skilled in the art.

Aside from a concern arising with regard to heating the entirestructure, which is a motivation for focusing on spot-welding methods,the possibility of soldering raises some of the same concern as seen inadhesive attachment: solder joints require a finite thickness which maybe difficult to control to sub-micron tolerances. If no precautions aretaken, and the feet are merely soldered down with a conventional solderpre-form covering the entire bottom of the foot, the final solderthickness, probably at least 0.5 mils in thickness, would be somewhatdifficult to control. The final height of the optic may varyaccordingly. To address this, methods reflecting those discussed abovewith regard to using adhesives may be employed. Specifically, a solderpre-form may be inserted into an inset “reservoir” using, for example,the same geometrical concepts as in FIGS. 59-63 above. Alternatively,solder may be loaded with spacer beads that maintain a steady heightduring positioning, which presumably takes place with molten solder, andafter positioning when the solder is hardened.

The foregoing descriptions serve to demonstrate the strength of theoverall approach of the present invention with respect to a multiplicityof differing bonding methods. It should be evident, in view of theexamples herein, that the structures and method of the present inventionare applicable over a wide range of attachment methods. For example, itis to be understood that there are many ways to bond two flat surfacestogether in a lamination, and many known methods of lamination willafford the ability to slide the feet prior to some bonding event.Clearly, most, if not all, viable bonding methods will be accompanied bysome degree of shift. In many cases, if the foot and mounting surfaceare at least partially in contact, frictional force aided by downwardbiasing of the foot, will reduce or eliminate attachment shift.

Inasmuch as the arrangements and associated methods disclosed herein maybe provided in a variety of different configurations and modified in anunlimited number of different ways, it should be understood that thepresent invention may be embodied in many other specific forms withoutdeparting from the spirit or scope of the invention. For example, FIG.64 illustrates a support bracket 900 including first and second webmembers or legs 902 and 904 which are hingedly attached to one anotherby a pair of hinges 906 (only one of which is visible) that are arrangedalong hinge axis 54. In this support bracket, however, end portions 908of the web members define feet in contact with support surface 45. Eachend portion further defines a notch region 910 that is intended for usein attaching the legs to support surface 45. The present applicationfurther contemplates support brackets having legs with end portions thatare configured, for example, to follow predefined slots, grooves orrails associated with one or more support surfaces. Therefore, thepresent examples and methods are to be considered as illustrative andnot restrictive, and the invention is not to be limited to the detailsgiven herein, but may be modified within the scope of the appendedclaims.

1. In a system for use in producing an optical assembly which itselfincludes a light path and an optical component to be positioned in saidlight path as part of the optical assembly, a method comprising thesteps of: defining a support surface as part of said optical assembly;providing movement means for controlling alignment movements of theoptical component in a particular way relative to the light path;supporting said optical component using at least one foot which formsone part of a support arrangement for supporting the optical component;directly engaging said foot with said movement means; biasing the footagainst the support surface in a movement mode which permits movement ofthe foot against the support surface; using the movement means, movingthe foot against the support surface in the movement mode to orient saidoptical component in said particular way with respect to said lightpath; and with continuing use of the movement means, biasing the footagainst the support surface in a locked mode in a way that is intendedlimit movement of the foot with respect to the support surface.
 2. Themethod of claim 1 including the step of using the movement means forbiasing the foot against the support surface in said movement mode andsaid locked mode.
 3. The method of claim 2 including the steps of usinga first force in said movement mode to bias the foot against the supportsurface and using a second force in said locked mode to bias the footagainst the support surface such that the second force is substantiallygreater than the first force.
 4. The method of claim 1 wherein saidsupport surface is at least generally planar and including the step ofconfiguring said foot to include an at least generally planar footsurface for engaging said support surface.
 5. The method of claim 4including the steps of engaging the foot surface against said footsurface with a coefficient of friction and configuring said movementmeans to apply a first biasing force in said movement mode and a secondbiasing force in said locked mode such that magnitudes of each of thefirst and second biasing forces are based, at least in part, on an areaof said foot surface and said coefficient of friction.
 6. The method ofclaim 5 including the step of selecting said second biasing force tocooperate with the coefficient of friction in the locked mode so as toat least limit lateral movement of the foot during attachment thereof tothe support surface.
 7. The method of claim 1 including the step ofproviding attachment means configured for cooperating with said movementmeans for fixedly attaching the foot to the support surface.
 8. Themethod of claim 7 including the step of laser welding said foot to thesupport surface using said attachment means.
 9. The method of claim 7including the step of lap welding said foot to said support surface. 10.The method of claim 7 including the step of forming said foot having (i)an at least generally plate-like configuration including, (ii) a lowersurface for at least initially engaging the support surface forming partof the optical assembly, (iii) an upper surface spaced-apart from thelower surface such that the foot includes a first thicknesstherebetween, (iv) and at least one weld region having a secondthickness which is less than said first thickness for use in welding thefoot to said support surface.
 11. The method of claim 10 including thesteps of further forming said foot such that said lower surface extendsacross said weld region and defining a stepped periphery in said uppersurface to provide a weldable surface which is spaced from said lowersurface by said second thickness.
 12. The method of claim 11 whereinsaid forming step forms said foot having a peripheral sidewall such thatthe upper surface extends from the peripheral sidewall to the weldregion to define a peripheral area which surrounds said weld region andwhich is configured for engaging said movement means for biasing theperipheral area toward the support surface which, in turn, biases thelower surface of the foot against said support surface in said movementmode and in said locked mode.
 13. The method of claim 12 including thestep of configuring the movement means for biasing the peripheral areaagainst the support surface prior to and during welding of the weldregion of the foot to the support surface.
 14. The method of claim 11including the step of configuring said movement means for engaging saidstepped periphery to move said foot against said support surface. 15.The method of claim 14 including the steps of configuring said movementmeans to include a movement arm having a distal end including aperipheral shoulder surrounding said distal end for engaging the steppedperiphery of the foot for use in biasing the foot against the supportsurface and for use in moving the foot against the support surface andforming said distal end to define a through-opening that is configuredfor passing a laser beam to the weld region for use in welding the weldregion of the foot to the support surface.